Hoof-and-Mouth Epidemic || Teacher for a Day || Trapping Genes || Do You Hear What I Hear? SEPTEMBER 2001

Untangling Proteins to Repaır the Brain FEATURES

18 Clearing Toxic Clumps 18 Making the Grade from the Brain Some researchers go all out to teach New discoveries link seemingly unrelated, fatal children about science. Follow their lead illnesses such as AlzheimerÕs disease and and kids will take notice. HuntingtonÕs disease to misshapen proteins, By Kathryn Brown providing hope for new treatments. By Maya Pines 22 College Student Meets 14 Quantifying Uncertainty Electron Man Initial panic turns to insight as students Neil Ferguson used mathematical modeling to embrace online learning and, in the process, help British policymakers stem the fast-spreading hoof-and-mouth epidemic. become critical thinkers. By Laura Spinney By M. Mitchell Waldrop 14

A farmworker disinfects a truckload of cattle slaughtered in the 2001 hoof-and-mouth epidemic at Horralane Farm in Devon County, some 236 miles southwest of London. DEPARTMENTS

2 NOTA BENE PERSPECTIVE

26 Repairing the Disconnect September 2001 || Volume 14 Number 4 3 PRESIDENT’S LETTER Between Research and Teaching HHMI TRUSTEES Putting Patients Back into James A. Baker, III, Esq. NEWS AND NOTES Senior Partner, Baker & Botts Biomedical Research Alexander G. Bearn, M.D. Executive Officer, American Philosophical Society 28 The Hidden World of Adjunct Professor, The Rockefeller University Cornell University Medical College UP FRONT Membrane Proteins Professor Emeritus of Medicine, Frank William Gay 30 Former President and Chief Executive Officer, summa Corporation 4 A Crystal-Clear Focus on Neuroscience of Music James H. Gilliam, Jr., Esq. Former Executive Vice President and General Counsel, Ion Channels 31 Mini-Courses in Moscow Beneficial Corporation Hanna H. Gray, Ph.D., CHAIRMAN 31 President Emeritus and Harry Pratt Judson Distinguished Service 6 Memorable Mouse New Museum Grants Awarded Professor of History, The University of Chicago 32 Garnett L. Keith Reason to Stay Another Year Chairman, SeaBridge Investment Advisors, L.L.C. PERSPECTIVE Former Vice Chairman and Chief Investment Officer, The Prudential 33 A River Runs Through Us Insurance Company of America Jeremy R. Knowles, D.Phil. 7 Giving Credit When Dean of the Faculty of Arts and Sciences and Amory Houghton 34 If You Can Name That Tone, Professor of Chemistry and Biochemistry, Harvard University Credit Is Due William R. Lummis, Esq. Thank Your Parents— Former Chairman of the Board of Directors and Your Music Teacher and Chief Executive Officer, The Howard Hughes Corporation Irving S. Shapiro, Esq., CHAIRMAN EMERITUS Of Counsel, Skadden, Arps, Slate, Meagher & Flom 35 Former Chairman and Chief Executive Officer, A Science Connection in E.I. du Pont de Nemours and Company Roxbury Anne M. Tatlock Chairman and Chief Executive Officer 35 New Undergraduate Fiduciary Trust Company International Competition HHMI OFFICERS Thomas R. Cech, Ph.D., President 36 HHMI Lab Book Peter J. Bruns, Ph.D., Vice President for Grants and Special Programs David A. Clayton, Ph.D., Vice President for Science Development 38 HANDS ON Stephen M. Cohen, Vice President and Chief Financial Officer Joan S. Leonard, Esq., Vice President and General Counsel May I Take Your Mouse Gerald M. Rubin, Ph.D., Vice President for Biomedical Research Order, Please? Nestor V. Santiago, Vice President and Chief Investment Officer

HHMI BULLETIN STAFF 40 CLOSE-UP Cori Vanchieri, Editor “Home-Grown” Proteins David Jarmul, Senior Editor Jim Keeley, Science Editor Build Synaptic Strength Jennifer Donovan, Education Editor 18 Patricia Foster, Manager of Publishing Kimberly Blanchard, Editorial Coordinator 42 FROM THE TOOLBOX Dean Trackman, Elizabeth Cowley, Copy Editors

22 Trapping the Genes that Steven Marcus, Peter Tarr, story editing Wire the Brain Kathy Savory, copy editing

David Herbick Design, Publication Design

44 HHMI ONLINE Telephone (301) 215 8855 n Fax (301) 215 8863 n www.hhmi.org The Bulletin is published by the HHMI Office of Communications, How to ZAP the Signals that Robert A. Potter, Director. Lead to Rheumatoid Arthritis © 2001 Howard Hughes Medical Institute Letters to the editor: We invite your comments. Send your letters via e-mail to [email protected] or regular mail to Letters, Office of On the Cover: Electron micrograph of a yeast prion Communications, Howard Hughes Medical Institute, 4000 Jones protein, called Sup35. Protein fibrils similar to Bridge Road, Chevy Chase, MD 20815-6789. We reserve the right to edit for space and clarity. Please also include your name, address these can aggregate and tangle in many degen- (e-mail or postal) and phone number. erative brain diseases, including Alzheimer's and mad cow disease. Image by Tony Kowal The opinions, beliefs and viewpoints expressed by authors in the HHMI Bulletin do not necessarily reflect the opinions, beliefs and viewpoints or

ODD ANDERSEN/AFP (LEFT), GARY HOVLAND (TOP RIGHT), DONNA TEREK (BOTTOM RIGHT) DONNA TEREK (BOTTOM RIGHT), (TOP HOVLAND GARY (LEFT), ODD ANDERSEN/AFP and Susan Lindquist official policies of the Howard Hughes Medical Institute. NOTA BENE

Federation of Biological Societies. The to be embo young investigators, scientists Six hhmi investigators were elected to award is given once every three years for in member countries whose early research the American Academy of Arts and health sciences research in Canada. has been distinguished. Sciences: Pietro De Camilli, Yale University School of Medicine; Brigid L. M. Hogan, Arthur L. Horwich, an hhmi investigator Thomas A. Steitz, an hhmi investigator at Vanderbilt University School of Medicine; at Yale University School of Medicine, won Yale University, was named one of three Richard L. Huganir, The Johns Hopkins the 2001 Hans Neurath Award from the winners of the 2001 Rosenstiel Award from University School of Medicine; Michael A. Hans Neurath Foundation and the Protein Brandeis University for distinguished work Marletta, University of Michigan Medical Society for contributions to protein science. in basic medical sciences. School; Roel Nusse, Stanford University School of Medicine; and Charles S. Zuker, Richard P. Lifton, an hhmi investigator at Joseph S. Takahashi, an hhmi investigator University of California, San Diego, School Yale University School of Medicine, won at Northwestern University, received the of Medicine. the 2001 Robert J. and Claire Pasarow 2001 W. Alden Spencer Award from the Medical Research Award for his cardiovas- College of Physicians and Surgeons of Graeme I. Bell, an hhmi investigator at cular research. He shared the award with Columbia University. The award honors The University of Chicago, won the 2000 Pasko Rakic, a Yale University neuropsychi- young scientists who have made original Naomi Berrie Award from Columbia atrist, and cancer researcher Alexander contributions to neurobiology. University for diabetes research achievement. Varhavsky of the California Institute of Technology. Two hhmi investigators, Marc Tessier- Two hhmi international research schol- Lavigne, University of California, San ars, B. Brett Finlay, University of British Roderick MacKinnon, an hhmi investiga- Francisco, and Brigid L. M. Hogan, Vanderbilt Columbia, and Roderick McInnes, the tor at The Rockefeller University, shared the University School of Medicine, were elected Hospital for Sick Children in Toronto, were 2001 Gairdner International Award for fellows of the Royal Society of London. elected fellows of the Royal Society of medical research with Clay Armstrong and Canada. Bertil Hille (see story, page 4). Bert Vogelstein, an hhmi investigator at The Johns Hopkins University School of Sergio Grinstein, an hhmi international George Mosialos of Greece and Laszlo Nagy Medicine, won the 2001 International research scholar at the Hospital for Sick of Hungary, both hhmi international Chiron Award for Biomedical Research and Children in Toronto, received the 2001 research scholars, were selected by the Training, given by the Italian National Malcolm Brown Award from the Canadian European Molecular Biology Organization Academy of Medicine.

Holiday Lectures on Science November 29 and 30, 2001 THE MEANING OF SEX Genes and Gender Four one-hour lectures by Barbara J. Meyer, Ph.D. David C. Page, M.D. HHMI Investigator HHMI Investigator University of California, Berkeley Massachusetts Institute of Technology

Simultaneous Webcast

For more information: www.holidaylectures.org

2 hhmi bulletin | september 2001 PRESIDENT’S LETTER

Putting Patients Back into Biomedical Research KAY CHERNUSH KAY ention “biomedical research” to people outside the scientific world and they may well envision as have other hhmi investigators who specialize in heart disease, a physician testing a new drug. They may not diabetes and other disorders, combining the latest techniques of realize that most biomedical researchers study molecular biology with their special perspectives as physicians. biological processes rather than specific dis- These “physician-scientists” work closely with patients, which is eases, and never interact with patients. In recent decades, in fact, not the case with all physicians engaged in research. Indeed, many Mmany of the most important discoveries in biomedical research M.D. and M.D./Ph.D. researchers pursue the same kinds of research have resulted from the study of fundamental biological problems, as Ph.D.s, focusing on basic biological questions; although they may such as how organisms develop, how genes function and how cells have an interest in certain diseases, they do not integrate their communicate. These studies, in all likelihood, were conducted research with the medical problems of the patients they treat. These using fruit flies, mice, yeast and other organisms—not human scientists have contributed tremendously to biology’s bounty, to be patients. That’s the kind of research we’ve emphasized at the sure, but the system should encourage physician-scientists to take Howard Hughes Medical Institute (hhmi), knowing that some full advantage of their special knowledge and experience. fraction of it inevitably contributes to advances in clinical medi- Wanting to make an impact on this situation, we recently cine that save people’s lives. announced an initiative at hhmi to encourage the support of For all of the discoveries that scientists around the world have patient-based biomedical research. In June, we sent letters to 119 made about oncogenes, tumor-suppressor genes, the cell cycle and medical schools and schools of public health, inviting them to nom- programmed cell death, however, fundamentally new treatments for inate physician-scientists to become hhmi investigators. We expect cancer patients have been slow to appear. We know far more about to appoint as many as 10 new investigators—a modest number, but the immune system and retroviruses than we did when aids one that builds on the Institute’s existing cadre of patient-oriented appeared 20 years ago, yet that disease remains a growing scourge investigators. Hopefully, other organizations may be stimulated to that is claiming untold millions of lives, particularly in the develop- increase their investments in this area as well. ing world. Researchers have identified more than a thousand genetic At the same time, hhmi is contributing to keeping the pipeline flaws involved in illnesses ranging from cystic fibrosis to Alzheimer’s of such scientists flowing through its research training fellowships disease, but physicians generally remain unable to fix these flaws. for medical students and the hhmi-nih Research Scholars Advances in basic science have been breathtaking, in other words, Program, which enables medical school students to join research but translating them into therapies has been difficult. teams for a year or two on the campus of the National Institutes of Ironically, our success in basic science now compels us to look Health. We are also considering additional ways to promote this back to the days when biomedical research almost always meant kind of research in the future. Having seen our patience in basic sci- working with patients. After all, what is seen in a test tube or a fruit ence pay off so handsomely, we believe it’s time to give “patient fly, for example, does not necessarily occur in a human being, and research” a broader meaning. only a small percentage of promising discoveries ends up having a direct impact on medicine. Fortunately, as we deepen our under- standing of how the human body operates at the cellular and molecular levels, it is becoming possible to carry out new kinds of “patient-oriented research” to learn which insights might pay off. The experience of hhmi investigators who do work directly with human patients demonstrates that such a patient-focused Thomas R. Cech approach can yield unique and potentially valuable medical President insights. Recent issues of the Bulletin, for instance, have described Howard Hughes Medical Institute Huda Zoghbi’s research at Baylor on mental retardation, Rick Lifton’s work at Yale on hypertension and Andy Chan’s work at Washington University on rheumatoid arthritis. Similarly, Bert Vogelstein at Johns Hopkins has worked closely with patients for many years as he helped uncover the genetic secrets of colon cancer,

hhmi bulletin | september 2001 3 muscle cells that is critical for nervous excitation. MacKin- non joined the effort, Up Front becoming Miller’s first stu- dent. Both scientists like to point out that Miller’s dog Gribet was already a lab A Crystal-Clear Focus member, but one can still safely say that MacKinnon on Ion Channels was Miller’s first research assistant who had the handy Rod MacKinnon forges his own path to study potassium gateways. attribute of opposable saac Newton acknowledged that his thumbs. scientific vision was sharper because electrical potential of membranes through- MacKinnon went on to he was “standing on the shoulders of out nature, thereby generating nerve impuls- medical school—against giants.”Science historian Gerald es and controlling muscle contraction, car- Miller’s advice—and then Holton, commenting on the accelerat- diac rhythm and hormone secretion.” practiced medicine for four Ied pace of research, gave Newton’s famous Intimate knowledge of the proteins is expect- years. Realizing then that he line a modern twist: “We are now uniquely ed to lead to the synthesis of pharmaceutical yearned to return to basic privileged to sit side-by-side with the giants compounds that can affect conditions direct- research, he made a pilgrim- on whose shoulders we stand.”Holton’s ly or indirectly related to ion flow. age to Miller’s lab to talk tongue-in-cheek comment certainly Although MacKinnon toyed with micro- about his assumption that describes the seating arrangement at the scopes as a youth, his serious interest in sci- such a move would require 1999 Albert Lasker Basic Medical Research ence was bestowed on him by his greatest sci- additional training and even Awards ceremony—at least from hhmi entific influence—his undergraduate adviser a Ph.D. Miller bluntly investigator Roderick MacKinnon’s point of at Brandeis University, Christopher Miller, informed his former student view. MacKinnon had the privilege of shar- also an hhmi investigator. Miller, just start- that the acquisition of a doc- ing the prestigious basic medical research ing his laboratory in the mid-1970s, was torate was redundant, as the prize with a personal giant—Clay M. Arm- looking at a number of processes involving M.D. already fulfilled that strong, of the University of Pennsylvania ion transport, including calcium pumping in qualification. School of Medicine—whose publications the sarcoplasmic reticulum, a mechanism in MacKinnon thus had an enormous influence on MacKinnon’s rejoined the Miller lab, as a development as a scientist. postdoctoral fellow investi- MacKinnon, Armstrong and Bertil Hille, gating potassium channels. “I of the University of Washington (and a had a sense I had a lot of member of the hhmi scientific review catching up to do,”MacKin- board, for neuroscience), were honored for non recalls. “And the only “elucidating the functional and structural way to really do that was, I DENNY CHRISTOPHER architecture of ion channel proteins.”MacK- thought, to knuckle down, and read and innon’s particular contribution was the deter- study and do as much as I could to learn on mination of the three-dimensional structure my own. I learned a lot from books and I of a potassium ion channel, using x-ray crys- learned a lot by just trying things out myself. tallography. Simply attempting to examine That made me very confident about learning the channel via this uncharted route was on my own. And that stuck with me.” deemed highly questionable by many and In 1989, MacKinnon started his own lab- foolhardy by some. Great risk, however, can oratory at Harvard to study ion channels bring great reward—and his ultimate success using a technique, called mutagenesis, that was judged by Armstrong, writing in the introduces variations in single amino acids in journal Science, to be “a remarkable accom- the protein sequence. Alterations in the pro- plishment” and “a dream come true for bio- tein’s behavior resulting from a change in a physicists.” lone amino acid reveal those regions of the

A great deal was at stake in MacKinnon’s LAB MACKINNON protein that are critical for its function. But quest to understand the as-yet-unseen ion In this potassium channel, potassium ions (green) the going is slow, like feeling one’s way channel proteins, as the Lasker proclamation lose a shell of water (red) to pass through a selec- through a dark room. “It became clear that in attests: “ion channel proteins … govern the tivity filter (ball-and-stick). order to understand the chemistry of the

4 hhmi bulletin | september 2001 painstakingly developed his new methodol- ogy—he succeeded in deducing the three- dimensional structure of the potassium ion channel protein. The structure revealed, for example, that the channel coaxed potassium ions with a portal that includes an array of oxygen atoms that surround the ion like a cage. The resulting chemical climate is simi- lar to the oxygen-rich, watery environment that the ions ordinarily prefer. The structure revealed why the potassi- um ion channel is selective, encouraging the flow of charged potassium while discourag- ing sodium ions. Both types of ions have the same charge (+1), and the sodium ion is sig- nificantly smaller, thus a simple sieve would accept both sodium and potassium ions. However, the large size of the oxygen cages—perfect fits for potassium ions—pre- vents the smaller sodium ions from ever falling under the electrostatic influence of enough individual oxygens to be compelled to make the trip through the pore. Nature’s clever structure thus solves multiple prob- lems simultaneously. Meanwhile, the accolades keep coming: MacKinnon won this year’s Gairdner Foun- dation International Award, which recog- nizes achievement in medical science. He once again rubbed shoulders with Arm- strong, who shared the Gairdner, along with Hille and Harvard cell biologist Marc Kirschner. MacKinnon is now focused on determining the structure of another species of potassium ion channel, one with a volt- age-sensitive gating system. This channel’s ion portal should be quite similar to that of the channel already elucidated. But an addi- MacKinnon is probing the structure of a potassium myself and talk to people to make sure I was tional structure that straddles the membrane channel that controls ion flow by reading the voltage on the right path,”he recalls. acts as a voltage meter, reading the voltage difference between the inside and outside of the cell. To make the transition to x-ray crystal- difference between the inside and outside of lography, MacKinnon accepted an offer the cell and opening or closing the gate to thing, we would have to see it,”MacKinnon from The Rockefeller University, and in control the flow of ions. “When we see that says, “because ultimately it is a structural 1996 moved to New York City. There, his structure,”MacKinnon says, “I think we’ll issue. And it was clear that mutagenesis could wife and a lone postdoc stood by him as he understand how the channel works.” never answer those questions.”He resolved to cranked up his research. “Rockefeller gave MacKinnon’s scientific reputation may attempt x-ray analysis of ion channels, me this big lab,” he recalls, laughing. “And be assured, but his research focus could which, being membrane proteins, are I was embarrassed to have people visit me. shift once again. “Right now I’m thrilled extremely difficult to crystallize. I thought, ‘How am I going to explain there with what I’m working on,” he says. “But I Miller advised him to start the project are only three of us? They’re going to take think I’ll reach a point where I want to slowly, on the side, while continuing to the lab away.’” think about something new. I’m not ready direct his bustling lab at Harvard in tried- The quiet, however, was apparently for it yet, but I’ll probably do it at least once and-true mutagenesis work. MacKinnon good for MacKinnon’s concentration. In more before I’m too old.” Don’t bother again considered and then declined his men- only two years—during which time he telling him he can’t. —STEVE MIRSKY tor’s advice. “I felt once again I could teach became an hhmi investigator and

hhmi bulletin | september 2001 5 Up Front their transgenic mouse was normal in all tain things, and not others.”Evolution has other respects when the inserted gene was probably ensured that certain memories be inactive and that no other systems had been strongly stored—for example, the location of affected during development. an abundant food source. Individual memory Memorable “Why do we have a brake on memory?” strengths, however, like those of our hypo- Kandel asks. “There are probably several rea- thetical ballplayer, may be more idiosyncratic. Mouse sons. One is that you probably don’t want to With an aging population, the detailed remember everything that you encounter. A understanding of the mechanisms of memory sk a pro ballplayer about a lot of things that happen to you are trivial, is of obvious interest in pharmaceutical devel- home run he hit 30 years ago and getting rid of that information fairly opment. “Clearly, there are two approaches,” and he may say, “Runner on rapidly is probably a good thing. We don’t Kandel says of any future memory drugs. first, two outs, two strikes, know what the limits of the storage capabili- “You act on positive regulators and make Seaver fastball up and inside, I ties of the brain are, but there probably is, them stronger, or you work on inhibitory reg- Apulled it down the line and into the second for each major category of learning, a limit ulators and make them weaker. So calcineurin row.”Ask the same man the date of his wed- as to how much you can put in there.” is a perfectly reasonable candidate.”The ding anniversary and the response may come The assumption that similar memory- enzyme is not an easy one, though, as Kandel in the form of a wrinkled forehead. Such is suppression systems exist in human brains points out: Existing calcineurin inhibitors the slippery stuff of memory. brings up the issue of filtering: We are no would also suppress the immune system hhmi investigator Eric Kandel was doubt constantly making judgments as to because of the enzyme’s roles in other path- awarded the Nobel Prize last October for his what is worthy of inclusion in our collection ways in the body. Nevertheless, the search for discoveries concerning the molecular nature of mental memorabilia. “The amazing thing techniques to impede memory-suppression of memory. In studies on invertebrates, Kan- about the mind is that it’s just filled with prej- genes is only in its infancy—and researchers del, of New York’s Columbia University, udice,”Kandel notes. “The mind is prepared will quite likely remember to follow in Kan- showed that memory storage depends on the to learn certain things and to remember cer- del’s first footstep. —STEVE MIRSKY coordinated expression of specific genes that code for proteins involved in making new synaptic connections. (The part of a ballplay- er’s brain in which game situations are stored must be a synaptic thicket.) There is a flip side, however, as Kandel reported in the March 9, 2001, issue of the journal Cell: Working with a transgenic mouse, he and his colleagues announced the first direct evidence in a mammal for genes involved in actually suppressing memory. (This discovery does not serve as an excuse for anniversary amne- sia.) In a previous mouse study, Kandel demonstrated that overexpression of the enzyme calcineurin interfered with memo- ry, providing damning circumstantial evi- dence that calcineurin is a memory suppres- sor. “But the really definitive evidence is when you remove it and the animal gets smarter,” Kandel says of the strategy used in the Cell study. Indeed, the animal did get smarter—in terms of memory of objects and locations. Removing calcineurin from the memo- ry-storage mechanism required the creation of a transgenic mouse with a gene for a cal- cineurin inhibitor that was controllable—it could be switched on and off by administra- tion of the antibiotic doxycycline. This sys- tem allowed the researchers to conclude that COOK TIMOTHY

6 hhmi bulletin | september 2001 PERSPECTIVE Giving Credit When Credit Is Due By Laurie Zoloth

y colleagues and I were intrigued recently by something that happened at several meetings of sarily takes responsibility as the “captain of the ship” and assumes biomedical researchers that we attended— that much essential support work will be done by people who are something clearly so common in the culture of not commonly credited when the outcome of a case is successful. basic science that the researchers themselves This situation is ironic because the practice of providing robust, Mprobably didn’t even notice. At the beginning or end of their public citation has a long tradition in the world of religious studies. talks, the scientists showed slides naming every person who con- In the Talmud, it is noted that failing to credit your insights, in the tributed to their research. They listed not only their faculty col- name of the one who has taught you, is akin to linguistically “killing leagues, but also postdocs, grad students, under- the teacher,” who is thereby “erased” in the textual graduates, and technicians and, in some cases, the sense. administrative and glass-washing staff. Typically, Some may argue that, of course, biomedical the scientists read each name and carefully delin- research differs from the humanities in some eated each person’s achievement—some even important ways, because, for example, it is experi- showed photos of their team members. mental or it requires teams—but I think these dif- Throughout their presentations, they noted where ferences are not as great as they might seem. In real- they had built on the research of others and which ity, much of our work in any university department colleagues had assisted them, often across scientif- would also be impossible without a team effort. ic disciplines. My experience attending scientific meetings We were also struck by how seriously the scien- has caused me to wonder what might happen if tists viewed their roles as mentors. bioethicists and others in the WILLIAM K. GEIGER Not only did they publicly credit humanities adopted practices like their junior colleagues and staff in “We should remember that honor those I observed at the biomedical their talks, but many brought post- research meetings. What would it docs or others to the conference for our work is never a personal be like if we fully credited everyone and included them in their conver- matter, but rather a collective who helped us think through “our” sations and meals. The junior col- ideas? What if we routinely recog- leagues, in turn, routinely and effort and a collective triumph.” nized the teachers who had proudly identified themselves in brought us along? How might we conversation and on their name begin to implement such norms? I badges as being in the laboratory of their mentors. It was obvious, have begun to discuss these ideas with colleagues and will be in other words, that everyone was taking responsibility for making curious to see where our discussions lead. these mentoring relationships work. Usually, when scientists interact with bioethicists, the expec- For someone from another discipline—in my own case, reli- tation is that those of us on the “ethics” side will help the scien- gious studies and ethics—this was an impressive set of “cultural tists think through the moral dimensions of their research. As my performances” that exemplified important operative values of the recent experience illustrates, however, the lessons actually flow in scientific community. Now I recognize that scientific research feeds both directions. Personally, I have already learned two ethical les- as much on competition and drive as it does on collaboration and sons from watching scientists in action and observing their cul- crediting, but the spirit of collegiality I witnessed at these meetings ture. First, all of us should identify with and take responsibility spurred me to take a fresh look at the norms of my own community for the “shops” we work in, honoring our mentors and mentoring of bioethics. It is not uncommon in the humanities, for example, to our students. Second, we should remember that honor for our hear tales of one scholar using or quoting another’s research with- work is never a personal matter, but rather a collective effort and out attribution. Nor is it unusual for scholars at the same institution a collective triumph, made possible by a team in which each con- to know nothing about the work of their colleagues, much less to tributor, whatever her role or status, is essential. feel a sense of association with that work. In the hospital, which is H the clinical setting where many bioethicists work, the model of con- Laurie Zoloth, an associate professor of social ethics and director of the Program versation, reporting and debate is often profoundly hierarchical. for Jewish Studies at San Francisco State University, is among a group of ethicists This structure emerges from a culture in which one person neces- who recently participated in scientific meetings at hhmi headquarters in Maryland.

hhmi bulletin | september 2001 7 Protein.Final 10/9/01 8:24 PM Page 8

Cl e a r i n g Toxi c Clumps fr omthe New discoveries link Bra i n seemingly unrelated, fatal illnesses such as Al z h e i m e r ’ s disease and ft er deca des of pessimism abou t the cha n c es of ever finding eff ective trea tm e nts for Alz h ei m er ’ s disease, Hu n t i n g t o n ’ s disease Hun ti n g t on’s disease, Lou Gehri g ’s disease and other progres s i ve kille rs of the brain suc h as mad cow disease, to misshapen proteins, sc i en t ists have produc ed a flood of ne w discoveries that link these outw a r dly unrela t ed ailments and sug ges t pr o viding hope for wa ys in whi c h they might be reverse d or prevent ed. What these diseases have in comm o n is a plague new treatments. of abn o rma l ly shaped prot eins that stic k togeth e r and des t roy brain cells . BY MAYA PINES ADif f erent prot eins are at fault in each disease. The y affect different parts of the brai n , and they produc e diverse symp toms . Yet all these prot ein s a re “m i s fo l ded ,” meaning they have strayed from their proper three - d i m en s i onal shape s ; ei t h er they never re ach ed these shapes as they em er ged from tin y prot ein factories inside the cell, or they became cor- rup ted. So,in s te a d of doing their normal jobs , these prot eins form aggre- gat es of in s o lu b le gunk, and in this process they devas t a t e the brai n . Some of th em — “ prion s” — a r e even infectio u s ; th e y cause mad cow dis- ease and its human cou n t erp a rt ,n ew - va riant Creutz f eld t - Ja k ob disease. The big qu e s ti on now is how to clear up—or preven t — pro tei n

8 h h m i b u l l e t i n | s e p t e m b e r 2 0 0 1 Protein.Final 10/9/01 8:24 PM Page 9

Prion proteins (red) aggreg a t e in a mo u s e neurob l a s toma cell that is infec ted with the prion disea s e called scr apie. The cell’s nucleus is shown in blue.

h h m i b u l l e t i n | s e p t e m b e r 2 0 0 1 9 clu m p s . Coming from several different directi on s , re s e a rch ers have is Alz h ei m er ’ s heredi t a r y in these families, but it also occu r s very early un c overed a va ri ety of pot ent ial targets for drugs . Equa l ly importa n t , in life: Memb ers may develo p the disease in their forties or fiftie s . th e y have learne d how to try out their new reme dies on yea s t , fl i e s , Certain families had errors in the gene that codes for amylo id precu r - worms or mice. “Thi n g s have rea l ly cha n g ed in the past few yea rs , ” sa ys so r prot ein (APP), a large molecule that is cut up by var ious enz y mes to Susan L. Li n d qu i s t ,n e wly ele cted director of the Whi t ehe a d Ins ti t ute for release peptid es of am yloi d - b eta — i n c luding the type that accu mu l a t es in Biom e dical Res e a r ch and forme r hh m i in ves ti ga t or at the Uni versi t y Alz h ei m er ’ s plaque s . In other families,tw o different gene s , pres eni l i n - 1 an d of Chi c a g o, who works mostly with yeast cells . “The first meetin g s I pres eni l i n - 2 ,ha d muta ti o ns that also produc e an increase in amyloi d - b eta . at t end ed abou t these diseases were so depres s i n g … . But now we have With these genes in hand, res e a r che rs cha r g ed ahead ,c re a ting tran s - se veral different kinds of st rat egies that look as if th e y might work ,s o genic mice and other animals in whi c h the gene s ’eff ects could be stud i e d everyone shares an optimism that just wasn’t there before. ” rap i d ly.One of th e ir first exp erim e nts showed that amylo id plaques were produc ed in the brains of tran s genic mice with muta t ed APP gene s , just like Am yloids in Alzheimer’s in those of Alz h ei m er ’ s patien t s . This exp erim e nt and others opene d the Some of the most promising res e a r ch invol ves the drea ded Alz h ei m er ’ s door to the pos s i bi l i t y of finding drug s that cou n t eract the eff ects of th e di s e a s e , whi c h robs so many older people of th e ir abil i t y to think or to muta t ed gene s . Several drug comp a n i e s ,i n c luding Bris to l - M yers Squi b b Co. remem b er, and then kills them. Alz h ei m er ’ s affects an astou n d i n g ly and Amg en, In c . ,a re now racing to develo p comp ounds that might pre- la r g e num b er of people—10 percent of those over age 62 and rou gh l y vent the enz y mes from snipping the precu rs o r prot ein and thereby stop the ha l f the popu l a ti o n over age 85. release of am yloi d - b eta . At the Nati o nal Ins ti t ute on Agin g , in Bal ti m o re, The brains of Alz h ei m er ’ s patie nts are typi c a l ly rid dl e d with stran ge , res e a r che rs develo ped an exp erim e ntal drug calle d phen s e rine that simply in s o lu b le “pl a qu e s , ”whi c h consist of am ylo id (small prot ein fibers that decr eases the produc tio n of the precu rs o r prot ein ,t h e reby lowering the level form a hard mass). For a long ti m e ,t h ere seeme d no way to get at the of am yloi d - b eta ; the drug is now in clinical tria l s . am yloi d — o r the disease. In 1999, res e a r che rs at Elan Pharma ceuticals in Sou th San Fran c i s - The “defining momen t , ”according to San g ram Sis od i a , a res e a r che r co announced they had made a vaccine against Alz h ei m er ’ s disease— on Alz h ei m er ’ s at the Uni versi t y of Chi c a g o, came with the discovery and that it worked in tran s genic mice. The vaccine contains bits of of sp ecific muta ti o ns in the dn a of certain unus ual families. Not onl y am yloi d - b eta , promp ting the mice to make antib odies against this sub - st a n c e that appa r ent l y prevent Alz h ei m er ’ s plaques from forming in the an i m a l s ’brai n s . Human trials of this vaccine began last year and demo n- st rat ed its safety. Now the comp a n y wil l test the vacci n e ’s eff i c ac y . Susan L. Li n d q uist can imagine several Beli e ving the vaccine too good to be tru e ,t wo independ ent tea m s pos s i b le strat egies for trea t ing diseases of sc i en ti s t s — o ne led by Peter St. Ge orge - H ysl o p, an hh m i in t erna - ca u s e d by misfol d ed prot ein s : Sc i e n- tio nal res e a r ch scholar at the Uni versi t y of Toront o, and the other by Pros p e c t s tists might find or des i g n prot eins or Da vid Morg an of the Uni versi t y of Sou th Florid a — r ecent l y set out to for d ru gs that would bind to their stic ky cha ll en g e its eff ectivene s s . In s te ad ,t h ey end ed up supp l ying evid enc e in surf a ces and prevent other molecu l e s its favor. Aft er mice with the equi val e nt of Alz h ei m er ’ s disease received Treat m e n t f rom get ting tra pped there . Th ey the vacc i n e ,t h eir performa n c e on memo ry tests cle a r ly improved. mi g ht des i g n prot eins that could insert Ano t h e r group at Tel Aviv Uni versi t y in Isr ael is bett ing on a differ- t h em s elves bet ween the aggrega tes and ent vacci n e ,A N - 1 7 9 2 , to prevent or treat Alz h ei m er ’s . Tho u g h nothing h elp break them up. Th ey might alter the is yet cert a i n ,s everal res e a r che rs— i n c luding Lindquist —think that at the cha p erone balance of the cell to help en su re that the prot ein s cu r rent rat e of sc i en t ific progress there is a good cha n c e of se eing trea t - attain their correct shape. Or they could try to increase the activ- me nts to slow down or prevent Alz h ei m er ’ s disease within five to ten yea rs . it y of the cell’ s prote a s om e , a sort of garb a g e can in the cytopl a s m that che ws up misfol d ed prot eins and gets rid of th em . A Clearance Mechanism A wi de ra n ge of diseases might be tre a ted with these Ano t h e r area “wh e re there’s sud d enl y a lot of optim i s m , ” according to ap proache s , she says. In add i ti o n to the 20 or so amylo id disor- Li n d qu i s t , is Hu n ti n g ton’s disease (HD), a rar e inherit ed disorder that ders and at least eig ht CAG- r epeat diseases, Park i n s o n’s disease is best known for having kille d the folk singer Woodie Guth ri e . Peopl e is a candidate. The re are some help ful trea tm e nts for Park i n s o n’s with this disease slowly deterio rat e both ment a l ly and physi c a l ly for toda y,but they do not get to the root of the disease,whi c h invol ves m ore than a dec ade , su f fering uncon tro ll a ble writhing movem en t s ag gregat es of the alpha - s y nu cl e in prot ein . Amyot rophic lateral al o ng the way. Tho u g h the hu n ti n g ti n gene was identi f i e d in 1993, af t er scl e rosis (ALS, also known as Lou Gehri g ’s disease), too, has been a long search, its normal functio n is stil l unknown and the mecha n i s m sh o wn to invol ve prot ein aggregat es—in this case, the prot ein of the disease remains a myst ery. Neverth el e s s , the gene ’s discovery has sup eroxi d e dismuta s e . le d to some interes t ing findings—and new approaches to trea tm en t . The re is even hope of trea t ing or stopping mad cow disease— The key to wh et h er the h u n ti n g ti n gene is normal or defective bovine spongi f orm enc epha l i ti s , or BSE—before the disease spread s turn e d out to lie in a kind of gene tic stutt er: a repetit ive sequen c e of th e to large num b ers of humans in the form of new - va r iant Creutz f eld t - dn a trip l e t CAG, whi c h codes for the amino acid glut a m i n e .S tretch- Jak ob disease.“I rea l ly do beli e ve that most of these neur odegene r- es of CA G “repea t s ”ap pear in every human bein g ’s hu n ti n g ti n gene , but at ive diseases can be attacked, ”Li n d q uist says .“ It may be five or ten in var ying leng t h s . Whe reas the normal gene has a sequen c e of betw een yea r s awa y,but we wil l be able to make a real difference . ” — M P 6 and 34 CAG repea t s , the abno rmal gene contains many more. In fact,

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ot h e r diseases caused by misfol d ed prot ei n s .“ It proves that mammals ha ve a cle a ra n c e mechanism that norma l ly remo ves this jun k , ” sa ys Arth ur L. Horwich , an hh m i in ve s ti ga tor at Yale Uni versi t y who stud - ies how prot eins fol d . He points out that HD and other diseases might be reversi b le if one could find ways to shut off the produc tio n of th e abn o rmal prot ein s . The cells that are dea d could not be revived, of cou rs e , but those that are sick might be cured .“ It could happen, ”he says, “i f one could intervene rap i d ly eno u gh . ” Prodding Proteins into Line One of the grea t est puzzles in bio l o gy is preci s e ly how the body’ s bill i on s of prot eins fold into their correct three- d i m en s i o nal shapes . Whe n amino acids are first strung togeth e r to make new prot ein s , th e y flop arou n d in s i d e the cell like cook ed spaghet ti . The n they rap i d ly cont ort into var - ious partia l ly fol d ed states before adopting their final, active form. Because scient ists knew that a special class of“cha p erone ”prot ein s gu i d e nascent prot eins towa r d their proper struc tu re ,t h ey wond ered if an ext ra supp l y of cha p erones would help to prevent prot ein misfol d - in g . For instance, could it prod emer g ing hu n ti n g tin prot eins suf f i - ci en t l y into line to prevent them from becoming toxic to neur ons? Nancy M. Boni n i , an hh m i in ves ti ga t or at the Uni versi t y of Penn - s ylva n i a , dec i ded to try this idea out in Dro sop h i l a bec a u s e , as she ex p l a i n ed , “l a te - on s et , progre s s ive diseases su ch as Al z h ei m er ’s or Park i n s o n’s can take months or yea r s to develo p in mouse models , but in fruit flies they take onl y 10 days. ”Ins te a d of working directl y wit h Hun ti n g t on’s, ho wever, she focu s e d on spinocerebellar ataxia type 3 Susan L. Lindquist has new optimism that work in yeast, flies and worms will (S C A 3 , also known as Macha do- Jo s e ph disease),one of at least eig ht dis- bring important insights into protein misfolding in several fatal diseases. eases caused by too many CAG repea t s . Aft er Bonini and her col leagues inserted the human SCA3 gene into an y stretch of dn a containing more than 40 of these repeats ensu r es that fr uit flies, th e y found that the flies’retin a s , whi c h contain nerve cells , rap - its bea r er wil l develo p Hun ti n g t on’s—and the grea t er the num b er of id ly degene rat ed. The res e a r che rs then produc ed a new strain of flies that repe a t s , the earl i er the disease stri kes and the gre a ter its feroc i ty. ha d both the SCA3 gene and a gene for a human cha p erone prot ein ,H s p 7 0 , Res e a r che rs also discovered that the abno rmal form of hu n ti n g ti n pro- in the hope the cha p erones would come to the cells ’res c u e . The y did.The duc es misfol d ed prot ein s , whi c h then stic k togeth e r in toxic clum p s cha p erones sup pres s e d the disease, and the flies’eyes rema i n e d norma l . in s i d e the patien t s ’ brain cells . Oth e r res e a r che rs, suc h as Huda Zoghbi , an hh m i in ves ti ga t or at People used to beli e ve that onc e Hun ti n g t on’s disease begin s , it is irre- Baylo r Coll e ge of Medicine in Hou s t on ,a re working with mice as well versi b le—that the gunk in the brain cells cannot be dissolved and that as flies.Zoghb i is working to find molecules that help sup press the dam- the brain cells are doome d to die. But whe n Ai Yam a m o t o and Rene Hen ag e caused by CAG repeats in the fly, th e n use the mouse model to of Colu m b ia Uni versi t y and their col leagues tes t ed this idea last yea r ,th e y examine how these molecules produc e their eff ects . found otherwi s e . Working wi t h mi c e that had been engi n e ered to The Workhorse: Yea s t ca r ry an HD gene , th e y devis e d a Li n d qu i s t ’s favorit e model orga n - wa y to tur n the gene on or off at i s m , h owever, is S a cch a ro myce s will . The n they showed that the dis- cerevis i a e , or baker’ s yea s t , whi c h ease progres s e d onl y as long as the can be manipulated easily and hu n ti n g ti n gene kept chur ning out grows ra p i dly. Even tu a lly, s h e m ore of the abn ormal pro tei n . ho pe s ,m odels of HD in yeast wil l S topping this produ cti on , t h ey provi de a ro ute for “f i rs t - l evel reported, “not onl y halts progres - sc r eens for pha rm a col o gical agent s si o n of the disease, but can reverse that might reverse some of t h e ag gregat e forma ti o n and progres - d a m a ge” f rom CAG - repeat dis- si ve motor decli n e . ” ea s e s . “Obvio u s l y, som e thing that This was tremen do u s l y good works in yeast might not work in ne ws—not onl y for Hun ti n g t on’s Two senile plaques from the brain of a person with Alzheimer's disea s e contai n mammalian cells , ” she says, “but pa ti e nts and their families but for de p os i t s of amyl o i d - b e ta protein surrounded by degenerating nerve endings. The you can screen thro u gh many, people conc erne d with any of th e black objects are neurofibrillary tangles within degenerating neuron s . m a ny more com pounds mu ch

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The ep i demic of m ad cow disease that clumps of abn o rmal prio n prot eins may damage the brai n . eru pted in Bri tish herds in 1986 has “Oth e r aggregati o n diseases are eit h e r sporad i c ,l i ke most cases of sl o wed down recent l y, proba b ly beca u s e Alz h ei m er ’s , or inherit ed, li k e Hun ti n g t on’s, ” sa ys Weis s m a n . “Wha t The Ma d the cou n t ry’ s meat indus t ry cha n g ed its ma k es mad cow disease so frigh t ening and unus ual is that it’s infectio u s . Co w m et h ods of rec ycling animal byprod- But that also gives you a cha n c e to eli m i n a t e it.” uc ts into cattle feed. All mammals,in c luding hum a n s ,c a r ry the prio n gene PrP ,whi c h was Co n n e c t i o n Yet an unknown num b er of app a r - di s c overed and named by Stanley Prus i n e r of uc s f in the 1980s.Prus i n - ent l y healthy people who ate infected meat er and others showed that tran s genic mice lacking the prio n gene were in Britain long ago may be incubating a fatal tot a l ly resistant to infectio n with scrap i e . “One of the keyst one exp erim en t s brain disorder, n ew - va riant Creut z feld t - Ja k ob in the prio n hypothesis was to dele te the prio n gene from mice and show disease (vCJD),whi c h seems to be caused by the same type of in f ectio u s that now they weren’t capable of acqui r ing the disease,”comm e nts Arthu r prot ein s , or prion s , as mad cow disease. At least 105 people have been L. Horwich , an hh m i in ves ti ga t or at Yale Uni versi t y.Whe n these mice were in f ected ,m o s t ly in Brit a i n , and 98 have alrea dy died. given a normal prio n gen e ,t h ey became sus c eptib le to scrapie agai n . Mad cow disease and vCJD kill so many brain cells that they leave Several res e a r ch teams have been looking for ways to eli m i n a t e holes in the vic tim ’s brai n , making it look like a sponge — wh i c h is why PrP- s c r apie aggregat es or to prevent them from forming in the first place. these disorders are calle d “sp on gi form” di s e a s e s . In sheep, the equi va- “We work with molecules that dena tu r e PrP prot ein , ”sa ys Fred Coh en , le nt disease has been known for abou t 300 yea r s as scrap i e , a fatal ill- at uc s f , whe re he coll a b orat es with Prus i n e r.“We learne d that bran ch e d ness that makes its vic tims tremb le and wobble fran ti c a l ly, oft en rub - pol yamines work well in cell culture . But they don’t cross the blo od- bing thems e lves raw against the fenc es of th e ir pens as they try to stay brain barrie r and don’t get into the brai n , so they cannot be used on ani- up ri gh t . The ir brai n s , too, ar e rid dl e d with holes. ma l s . However, th e y could stil l be qui t e useful as disinfecta n t s . ”The re Was it scrapie that infected Brit ish cows? Maybe. But how cou l d ar e no good disinfectants against abno rmal prion s , and cases of peopl e in f ectious prio ns overcome the usual barrie r betw een species? Recent stud - con tracting Creut z fel d t - Ja kob disease from su r gical instru m ents or ies by Jonathan S. Weis s m a n , an hh m i in ves ti ga t or at the Uni versi t y of fr om corneal transplants have been reported. Cal i f orni a , San Fran c i s c o (uc s f ), and gradua t e stud ent Peter Chi e n pro- “We also found that some antib odies actua l ly clear prio ns from vid e a pos s i b le answer. Working with two different species of ye a s t ,t h ey mouse cells infected with scrap i e , ”Coh e n says. “This argues that prio n sh o wed that a yeast prion , Sup 3 5 , can misfold into several “dra m a ti c a l ly diseases may be trea t a b le with antib odi e s . ”Most recent l y,Prus i n e r's tea m di f f erent ”in f ectious shapes ; this property ena b les abno rmal prio ns from exa m i n e d a large num b er of comp ounds that are known to cross the one yeast strain to interact with normal prio n prot eins from other strai n s , blo od- b rain barrie r and discovered that two older drugs — ch l o rpro- in d ucing them to adopt similarly abno rmal shapes . In ye a s t ,a bn orma l ma z i n e , an antip s y cho ti c , and qui n ac ri n e , an antim a l a r ial agent — p re- prio n prot eins clump togeth e r and lose their normal activit y.In mammals, vent the forma ti o n of PrP scrap i e . The y are so enco u ra g ed by this find- ing that they sug gest the drug s are “i m m ed i a t e candidates ” for trea ti n g Jonathan S. Weissman (right) and grad student Peter Chien determined how Creutz f eld t - Ja k ob disease and other prio n diseases, and have begu n prions can jump from species to species. tes t ing them in people dying from CJD. S ti ll , the best approach would be pre- venti on , Weissman points out. The new- va r i- ant CJD is “a very aggres s i ve disease,”he says. “Once you have the symptoms of vCJD, it will be difficult to treat.” Because there’s no blood test for the disease,the American Red Cross announced in May that it would stop accepting blo od from anyone who has spent as little as three months in the United King- dom or six months els e whe re in Eur ope dur - ing the past two decades. Weissman would like to know wh a t makes cows or people susceptible to these d i s e a s e s . Si n ce some sheep are natu ra lly resistant to scrapie, it might be possible to find bul ls that are natura l ly resistant to prio n diseases and use them to breed more-resist- ant cattle herds.“If we can learn where mad cow disease came from and how it is trans- mitted,” he says,“we may be able to ensure that the cattle supply is completely free of m ad cow disease—and to prevent futu re outbreaks.” — M P

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m ore ra p i dly and mu ch more erones just bind to partl y fol d ed pro- che a p l y in yeast than you could in teins and keep them from getti n g mammalian neur onal syst ems . ” in t o trou bl e , but Hsp104 can actu- Even more import a n t , per- al ly take a struc tur e and cha n g e it.It ha p s , res e a r ch on yeast may lead to can take apart newly forme d aggre- s ome basic insigh t s . “The prob- gat es that are caused by heat stres s . le m of why prot eins misfol d — a n d So I prefer to call it a remo deli n g why that is associated with toxic- fa ctor rat h e r than a cha p erone . i ty—is very com p l ex ,” L i n d qu i s t “The n we got a call from Yur y sa ys .“ It’s suc h a comp l e x proble m Che rnof f , ” Li n d q uist reca ll s . Now that I think it’s really important Mu s cle cells in a worm's body wall show the effec t of an excess of CAG rep e a ts , at Georg ia Tech, Che rnof f was then for lots of people to be working on as occurs in Huntington ’s disea s e. A normal C. elegans wh o se DNA contains no a scient ist in Susan Liebma n ’s lab it, and to be approaching it from mo r e than 19 CAG rep e a t s produces protein that is distr i b u t ed even l y at the Un ivers i ty of Ill i n ois wh o different angles.” th r oughout the muscle cells (left). With too many CAG rep e a t s, the protei n was stud ying [PSI], a gene tic trai t One rea s o n for the comp l ex i - forms uneven clumps (right). in yeast that seem ed to be dis- ty is that “th e re seem to be a var i- obeying Mend el’ s laws of in h e ri- ety of di f f erent ways in whi c h prot eins can misfol d , ” she ex p l a i n s .“ In t a n ce .( Su ch traits used to be labele d “non - M end eli a n , ”but now they are ad d i ti on , t h ere are different kinds of a ggrega te s .” To make matters in d i c a t ed by brackets : [PSI].) “H e had been trying to clo ne genes that worse , “ag gregat ed prot eins are rea l ly miserab le to work wit h , ”she says. con trol [PSI]’s inherit a n ce , ” L i n d quist rec a ll s , “and he said the on e “You can’t cryst a ll i z e some thing that’s an aggregate , so you can’t use x- clo ne that rea l ly had a big eff ect was the gene for this prot ein we had been ray cryst a ll o grap hy. You can’t use any of the typical tools for the stud y working on, Hs p 1 0 4 . We hadn ’t yet publi s h e d muc h on its molecu l a r of prot ein struc ture , whi c h requi r e the prot ein to be eit h e r in solutio n me cha n i s m s . or free. So we’re reduc ed to using some fairly prim i t ive tool s , and whe n “Susan Liebman had been working on [PSI] for a long , lo ng tim e . you see a big blo b inside a cell you can’t tell whet h e r it’s the same as So we coll a b orat ed with her and Yur y, and we showed that you cou l d an o t h e r blo b.Yet one blo b might be toxic and the other not. One might cu r e yeast cells of this trait just by tran s i en t l y cha n g ing the level of provid e a surf a ce for other prot eins to bind on, while others don’t. Hs p 1 0 4 . The normal state was then passed on from one yeast gene ra- “I t’s not even cle a r ,”she add s ,“ wh et h e r it’s the aggregat e per se that’s tio n to the next . This was a very strong argument that the trait was inher- toxi c . Could it be some earli e r misfol d ed intermed i a t e? The large aggre- it ed throu g h a prot ein struc tur e”—in other word s ,t h ro u gh a prion . gat es might be the cell’ s way of se que s t ering material to prot ect itself … . A little later, Li n d q uist discovered that Hsp104 also cont rols the This fundamental proble m has not been solved. ” ag gregati o n state of the hun ti n g t in prot ein , at least in yea s t . “So now At least in Hun ti n g t on’s disease,whi c h Lindquist has been stud ying in we’re using Hsp104 in yeast to cha n g e the aggregati o n state of hun ti n g ti n yeast cells , she beli e ves that the rea l ly dangerous state is the small aggregate s . and to test some models of ho w its toxi c i t y might aris e , ”she says. Next , “B ut we don’t know how muc h that applies to other diseases,”she says. she plans to look for “ag ents that might interfere with the toxi c i t y,”fi rs t in ye a s t ,t h en in mammals. The Influence of Pri o n s Li n d q uist beli e ves prio ns arise whe n certain normal prot eins acci - Yeast may in fact provid e the key to understanding not onl y amylo id dis- den t a lly produ ce folding interm ed i a tes that have a sti cky su rf ace . eases and CAG- r epeat diseases,but also “sp ongi f orm enc epha l op a t h i e s ” “That surf a ce provid es a temp l a t e for other partia l ly unfol d ed prot ein s , suc h as mad cow disease,whi c h have been attrib uted to prion s . The very wh i ch bind with it and wind up get ting tra pped ,” she ex p l a i n s .“ L i t t l e id ea of prio ns makes many scient ists uneasy because it vio l a t es the funda- a ggrega tes of pro tein are then passed on from mother cell to daugh- me ntal principle that the pres en c e of nucl e ic aci d s , suc h as DNA, is essen- ter cell thro u gh the cytop l a s m ,and wh en the daugh ter cell starts mak- tial both to inherit a n c e and infection . Yet prio ns produc e clumps in the ing her own pro tei n s , these have the same capac i ty to get tra pped on brain that are infectious even l a r ger aggrega te s . th o u g h no nucl e ic acid seems to be “ It’s very heri t a bl e . It’s very in vol ved. In add i ti on , prio ns can reproduc i bl e , ” Li n d q uist says. “I f pass their traits acr oss gene rati on s . you cross a cell that has a pri on Li n d q uist came to prio ns by trait with a cell that doe s n’t , t h e acci d ent . “We just happene d to be pri on trait is alw ays dom i n a n t working on a prot ein calle d Hsp104, because it’s got that stic ky surf a ce, whi c h is a heat-shock prot ein — i t ’s and the other prot eins join up to it. very important for thermal tol e r- The n all the cell’ s progeny wil l have an c e in yea s t , ”she says. “Oth e r cha p - that trait in them. ” To devel op approri a te te a t- Ar thur L. Horwich believes that men t s , it ’s essent ial to underst a n d Hu n t i n g to n ’s disea s e and similar disor - the basic mechanisms of prot ein de r s might be rever sible, if abnormal mi s fo l d i n g ,as well as how misfol d - pr otein prod u c tion could be shut down. ing can perpetua t e itself , she says. H

s e p t e m b e r 2 0 0 1 13 Hoof&Mouth.Final 10/9/01 2:04 PM Page 14 Qua ntifying Neil Ferguson used mathematical modeling to help British policymakers stem the fast-spreading hoof- and-mouth epidemic. BY LAURA SPINNEY

n mid-Mar ch, whe n the Brit ish epi d emic of ho of- a n d - m o u th disease (h m d) appe a red to be spiraling out of con tro l , the govern m en t a ppe a l ed to the co u n try ’s scien tists for hel p.Am ong those wh o an s w ered the call was Neil Ferg u s o n at the Imp erial Coll e ge Scho ol of Medicine in Lond on, an hh m i in t erna ti o nal res e a r ch scholar who develo ps mathema t ical models of in f ectious diseases. Ferg u s o n’s models are informe d by the bio l o gy of di s e a s e s — f r om the molecu l a r- l e vel actio n of pa t h o gens and host immun i t y to the envir on m en t a l ,s ocial and beha vio ral factors that work at the popu l a - tio n level. His models of hm d le d him to draw some stark conc lus i on s : The exi s t ing cont rols weren’t working and the long dela ys betw een diagnosis and Isl a u gh t er of in f ected animals were fueling the epi d emi c . A more aggres s i ve eradi c a ti o n program was needed. This would invol ve the culling of animals on farms sus p ected of in f ectio n within 24 hours, wit h o u t waiting for conf i rm a ti o n from the lab; al l animals on neigh b oring farms had to be culle d within 48 hours. The other three modeling teams that advis e d the governm e nt came to the same conc lus i on s . The military was calle d in, and at the peak of the outbrea k , so me 2000 troops were invol ved in the eradi c a ti o n natio nwide , sup ported by up to 1000 pol i c e off i - cers. Almost 2.5 milli o n animals were slaught ered in 11 week s , requi r ing bur ial pits equi val e nt to 200 Olymp i c - s i z e swimming pool s . Dur ing a visit to Cum b ria , one of the cou n t ies hardest hit by the disease (see map, pa g e 16), Ferg u s o n partic i p a t ed in one of the army’ s daily operati o ns meetin gs . Whi l e li s t ening to the soldiers talk abou t the logis t ics of the operati on , the ram i f i c a ti o ns of hi s res e a r ch became cle a r .On a sepa ra t e occa s i on , he spok e to a group of fa rm e rs and came fa ce- to - f a ce with their conc ern s .“ Ha l f the farme rs in that room had lost their farms al re a dy because of ho of- a n d - m o ut h , ” he says. “I estim a t ed that by the end of the epi - demi c , up to 70 percent of Cum b rian farms might be affected. That num b er shocked th em , but it is tur ning out to be abou t righ t . ” Ano t h e r memb er of the Imp erial tea m , Chr istl Donn e lly, found hersel f conf r ont ed by a group of an g ry, vocal farme rs in Devon ,a n o t h er badly hit cou n t y in the south wes t pa r t of the cou n t ry. She des c ri b ed feeling “ou t on a limb.” S ti ll ,m o tivat ed by a des i r e to off er practical help in a des p erat e situa ti on , Ferg u s o n and his col leagues defend their rec- omm en d a ti o ns vig orou s l y.“The hm d epi d emic has significant econo mic cons e quen ce s for the cou n t ry, whi c h I hope my work might help to minimize, ”he says. As soon as the governm e nt rele a s e d its data on infected cases to the Imp erial team in Mar ch, Ferg u s o n and his col leagues spent an intens i ve 10 days feeding crit ical num b ers in t o their models . By calculating the likeli h o od that one farm would infect another in a

Neil Ferg u s on wor k ed to minimize the loss es experienced by U.K. far m e r s like the one at right, who wal k s past his cows while fires incinerat e animals at a nearby farm.

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pa r ticular length of tim e , given the sepa ra ti o n demic that tailed off mo re slowly. “Ex t ens i ve betw een farms and the dynamics of the natio n- U. K. HOOF-A N D - M OUTH OU T B R EA K cu l ling is sadly the onl y optio n for cont roll i n g wid e agric u l tu r al netw ork ,t h ey were able to pre- Di s tribution of infections by county the current Brit ish epi d emi c , ”the Imp erial tea m di c t the futur e cou r se of the epi d emic and to ran k conc lud ed. CAS ES PER COU N TY the pot ent ial eff ects of di f f erent interventi on s . 0 The policy has been largely suc ces s f u l . By 1–10 the end of May, the num b er of in f ected farms REDUCING R0 1 1–10 0 was dropping by half ea ch fortni g ht and R0 wa s Sp eci f i c a l ly,th e y measur ed the impact of th o s e 101 and up un d er 1.0. Ferg u s o n’s advic e was neverth e less to i n terven ti ons on R0, the case-reprodu cti on maintain the aggres s i ve cull until the disease rati o , or averag e num b er of se cond a r y cases was comp l e tely eradi c a t ed. The second serio u s gene rat ed by one prim a r y case of in f ection . By ou tbreak in previo u s l y unaffected Yorks h i r e in defi n i ti on , whe n this figure drops belo w 1.0 the mi d - M ay cou l d , he sug ge s t s ,h ave been an indi- epi d emic can no long er sustain itself . “Wha t rect res ult of the governm en t ’s deci s i o n to rela x cont rol measur es do,whet h e r it’s culling or vac- the pol i c y , all o wing veterin a r ians more discre- ci n a ti o n or a whole ran g e of ot h e r things, is to tio n as to whi c h animals were slaught ered on reduc e that qua n ti t y,ma k e the disease less infec- fa r ms that nei gh bored infected one s . Even tak- ti o u s , give it less ch a n ce to spre ad to other ing that outbreak into accou n t , the epi d emic has fa rm s , ” sa ys Ferg u s on . He and his team were decli n e d in line with the tea m ’s predi c tion s . si m p l y looking for the qui c kest and most eff ec- tive way to bring R0 down. OVERSIMPLIFYING REALITY? Pub lishing their res ults in the May 11,20 0 1 , S ti ll ,s ome leading hm d exp erts have des c ri b ed is s ue of Sci en c e, th e y argued that vacci n a ti o n the policy as exces s i ve. Ale x Dona l d s on ,h e a d of would be less eff ective than culling as an eme r- the Ins ti t ute for Animal Health laborat ory in gency res p ons e . Alt h o u g h vacci n a ti o n reduc es the popu l a ti o n of an i - Pi r brigh t , Sur rey, and a governm e nt advis e r himself , has criti c i z ed the mals sus c eptib le to the disease, it does not reduc e the infectiousness of ma t h em a t ical models for oversi m p l i f y ing rea l i t y. In a stud y publi s h e d in those animals alrea dy cont a m i n a t ed, and so, does not reduc e tran s m i s - the Veterin a r y Reco r d on May 19, 20 0 1 , he argued that the models were si on . Sim i l a r ly, cu l ling of in f ected farms alone , le a ving their seemi n g ly ba s e d on an averag e animal, and did not allo w for differenc es in infec- he a l t h y neigh b ors untou ch ed , would be insuf f i c i en t . By failing to stem tivit y, im mu n i t y and tran s m i s s i o n rou tes among cows ,p i gs and sheep. ne wly acqui r ed though not-yet- a pp a r ent infection s , suc h res t ric ted culli n g Fred Brown of the U.S . Depa r tme nt of Agric u l tu r e’s Plum Isl a n d would leave R0 at or around the crit ical thres h o l d , resu l t ing in a larger epi - Animal Disease Cent er in Greenp ort, New York, who was asked by Modeling Common Human Diseases

he same tech n i ques that Nei l avai l a bl e . He is trying to predi c t futur e inci- im mu n i z a ti o n against chi c kenp ox and the resu l t - Ferg u s o n has used to model hm d denc e trends in the pos t v acci n a ti o n era, as well ing reduc tio n in natur al immun i t y to it is lead- in animals are shedding light on as how health scares abou t vacci n e s — p a r tic u - ing to a rise in cases of sh i n gl e s , a clo s e ly rela t ed so me of the most comm o n chi l d - l a rly the con troversial com bi n ed measles- (and more serious) adult disease that is caused ho od infection s , as well as kille rs mu m p s - ru bella vacc i n e — wi ll affect those by the same viru s . “N eit h e r exercise would be sTu ch as h iv / a i d s. The Im perial group is trend s . pos s i b le wit h o u t the sort of mac r oan a l ytical tool in vol ved in an interna ti o nal coll a b orati o n wit h Sim i l a r ly, Ferg u s o n is analyzing how mass provid ed by mathema t ical models , ” he says. the Joint Un i ted Na ti ons Programme on He also intends to stud y how diseases evol ve hiv / a i d s (una i d s ) in Gene va to map this un d er sele ctio n pres su re s , the two main one s di s e a s e , whi c h pres e nts an eno rmous cha ll en g e being how a pathogen evol ves throu g h interac- to modele rs. tio n with the host’s immune syst em and how it The re are uncerta i n t ies abou t the disease evol ves res i s t a n c e to drugs . In add i ti o n to the process itself — h o w the vir us interacts with its obvious clinical implicatio ns of this res e a r ch ,i t host—and abou t the beha vio rs that wil l shape wil l have broader scient ific cons e quen ce s . the epi d emi c . As Berna r d Schwa rt l a n d er,he a d of As Ferg u s o n exp l a i n s , “I am fundament a l ly epi d emi o l o gy at una i d s ,no te s : Peopl e ’s sexu a l in t eres t ed in the popu l a ti o n bio l o gy of pa t h o gen procli vit ies “ar e not stamped on their forehe ad s . ” evol ution , because it’s a microcosm for evol utio n Fer g u s on’s group is also working on as a who l e . But since [pathogen evol utio n] hap- m e a s l e s ,p a rt ly because the bio l o gy of the dis- pens on a muc h faster time scale than in other ease is rela t ively well known and deta i l e d his- Mo r e than half of the people trea t ed at this clinic orga n i s m s , you can actua l ly obs e rve it and the torical records of its patterns of in c i d enc e are in Ndwed w e, South Africa, are HIV posi t i ve . processes shaping it directl y.” — LS

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S ci en ce to revie w the Imp erial grou p ’s May 11 paper, sa ys that there are so many unknowns in the spre ad of the disease—including ill ega l H O O F-A N D - M OUTH DIS EASE IN THE U. K. Confirmed daily cases, 200 1 mo veme nts of li ves t ock and the beha vio r of deer and other wil dl i f e pop- ul a ti o ns—that suc h models could not pos s i b ly be accu ra te . Ferg u s o n says suc h crit icisms show a lack of un d erstanding of mo d- eli n g .Inf ectio n grows geome tric a l ly in a popu l a ti on , giving an epi d emi c the cha r acteris t ic shape of an exp onen t ial curve. Bas e d on this prin c i p l e , a mathema t ical model divid es a popu l a ti o n into three cla s s e s : those who ar e sus c eptibl e , those who are infected and those who have recovered. It consists of a set of equa ti o ns that repres e nts the epi d emic process as a feed- ba ck loop whe re the rat e at whi c h sus c eptib le individ uals become infect- ed is proportio nal to the num b er of those alrea dy infected. At that level, a model is indeed a simplificatio n of rea l i t y. The com- pl ex i t ies come in with the diverse beha vio rs of di f f erent diseases—the

i m mu n i ty gen era ted by the pathogen , the infectivi ty and ro utes of Sou r ce: Rep o r t of the Committee of Inquiry on Foo t-and-Mouth Disea s e 1968 and MAFF 200 1 tran s m i s s i o n wil l var y.Whe n any of these param e ters are unknown ,s ays Ferg u s on , or whe n the rele vant data are not avai l a bl e , the skill is to fac- in c u b a t e vCJD for long er period s . The evid enc e comes from Coll i n g e’s tor them into the equa ti on s , with alterna t ive scena r ios weigh t ed accord- st udies of ku ru , a similar disease that is stil l affecting eld erly memb ers ing to their proba bi l i ti e s .E a ch alterna t ive gene rat es a different outcome , of the Fore trib e of Papua New Guinea more than 40 yea r s after their providing pol i c ym a k ers with a worst-case scena ri o , a best-case sce- practic e of ea t ing the brains of dea d rela t ives was banned. na r io and a spectrum in-betw een from whi c h to make their deci s i on s . His findings rai s e d fea r s that the Imp erial team had vas t l y under- As more hard data come in,the equa ti o ns can be adju s t ed to give a bet- es ti m a t ed the size of the epi d emi c . But Ferg u s o n points out that they ter fit and more precise proje ction s . ne ver exclud ed the pos s i bi l i t y that the rest of the popu l a ti o n might be Ine vit a b ly, sa ys Roy And ers on ,h e ad of the Imp erial group and one of sus c eptibl e . The onl y assum p tio n they made, and one he thinks is jus - the pione ers of in f ectious-disease modeli n g ,whe n you are dealing with an tif i ed , was that the distrib utio n of in c u b a ti o n perio ds is likely to be sim- ong oing epi d emic the most current data are less precise than you wou l d ilar to that of ot h e r prio n diseases. In the case of k u ru , for instance ,t h e li ke . Gi ven the urgenc y , ho wever,“th e re is a scient ific comp romise to be in c u b a ti o n perio d var ies from 2 yea r s to 35 yea rs , rising to a single pea k ma de betw een detail and some thing that is suf f i c i en t l y robust to give a qua l - at around 15 yea rs . By defi n i ti on , the vCJD cases that have alrea dy it a t ive guide to pol i c y ,”he says. One of the rea s o ns for stud ying animal dis- come to light are those with the shortest incubatio n period s . It may be eases suc h as hm d , adds Ferg u s on , is to “off er the opportun i t y for muc h 20 yea r s before we see the cases with long er incubation s , he says. mo re comp l e te data to be coll e cted easily and for exp erim e ntal and epi - The molecular bio l o gical evid enc e is therefore not at odds with the demi o l o gical studies to be carrie d out that are not pos s i b le in hum a n s . ” mo dels , Ferg u s o n maintains,or the worst-case estim a t e his team gene rat - ed.S ti ll , one thing he may have to correct for as the epi d emic unfolds is how MERGING MODELS those gene tic sus c eptibi l i t ies interact with beha vio r. In vCJD, the incuba- Whe n it comes to understanding how a disease beha ve s ,m odele rs are tio n perio d is not determi n e d solely by the underlying gene tics but also by cons t a n t l y delug ed with new informa ti o n from well- e s t a bl i s h e d field s the amount of in f ected material inges t ed. The more infected meat a per- suc h as immun o l o gy—the discovery of ne w immun o l o gical markers of so n eats,the soone r he or she succ u m b s . “We don’t have any idea of the dis- di s e a s e , for instance—as well as rela t ively young fields suc h as molec- trib utio n of dos e s , but it was proba b ly qui t e wide , and that wil l mask a lot ular bio l o gy.At the mom en t ,d i f ferent aspects of disease tend to be mod- of the add i ti o nal vari a ti o n you might get from the gene tic s , ”sa ys Ferg u s on . el ed sep a ra tely, and the modeling com mu n i ty divi des ro u gh ly into Mar tin Nowak of the Ins ti t ute for Advan c ed Stud y in Prin c eton, New those who model the sprea d of a disease within an individ ual and those Jerse y,who models the sprea d of vir uses within an individu a l , beli e ves the who model it within a popu l a ti on . The proble m with these partia l main cha ll en g e facing the field now is to establish a single theoretic a l mo del s ,h owever, is that they tend to overlo ok interactio ns among the fra m e work that wil l accomm od a t e all the avai l a b le informa ti o n and its pos - ma n y different factors that shape an epi d emi c . si b le interaction s .“ I n the end , one wil l build models whe re a vir us spread s New- va r iant Creutz f eld t - Ja k ob Disease (vCJD), the human form of within an infected individ ual and within a popu l a ti on , ”he says. so - c a ll e d mad cow disease (see story,pa g e 8),is a good example of the dif- Ferg u s o n hopes to start develo ping the meth o dol o gy to build these fi c u l t y of mo deling interaction s . In the August 2000 issue of Natu r e, th e comp rehen s i ve models over the next five yea r s to answer basic scienc e Imp erial team estim a t ed that the predi c ted Brit ish epi d emic would likely que s ti o ns abou t evol utio n as well as public health (see box ,p a ge 16). He af f ect no more than 136,000 peopl e . That was a preli m i n a r y proje ction , beli e ves this next gene rati o n of mo dels wil l make pos s i b le more preci s e ba s e d on data rela t ing to the 70 or so cases that had been recorded at that predi c tion s , and that modeling wil l play an increa s i n g ly important rol e tim e . But all of those early cases came from the 40 percent of the popu l a - in disease cont rol . Even now, he says ,m ore and more scient ists are rea l - tio n that shares a certain identi f i a b le gene tic makeup ,or geno t ype. The re izing that the val ue of mo deling lies in qua n ti f y ing uncerta i n t y, in mak- was a hope at the time that the other 60 percent might be immune to vCJD. ing it managea b le for pol i c ym a k ers. Sin c e then ,m o l ecular bio l o gical evid enc e coll e cted by John Coll i n g e Ask him if th e re is any disease that can’t be modeled , and he smiles: of Imp erial Coll e ge and Uni versi t y Coll e ge Lond on has indicated that, “The re is nothing that can’t be modeled , but there are lots of th i n g s that rat h e r than being immun e , people with different geno t ypes might jus t ca n ’t be modele d easily.” H

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✎ SomeGrade res e a r chers go all out to teach children about science. BY KAT H RYN BROW N

Rohit Var ma heads a $6 milli o n eye stud y. He works with leading scienti s t s . He can le ctur e off the top of his head. So shouldn’t tea ching a class of ki n d er ga rtne rs be a snap for him? Not at all. Two yea r s ago,Varm a , an opht h a l m o l o gist at the Uni versi t y of Sout h e rn Cal i f orn i a ,c a rrie d a skele ton— du b bed Peter— t o his son’s kinderga r ten cla s s . He qui ck l y launche d into the basics of bone s , making it all the way down to the rib cage before a gir l poin t edly rai s e d her hand.Sh e wa n t ed to know one thing:Whe re did the skele ton come from? “The n the dam broke , ” Var ma reca ll s . Sud d enl y, an o t h e r child—and then another— j oi n e d in the cho rus of que s ti on s . Was this a dea d perso n? What happene d? How did Var ma get hold of the body? Var ma shot a look at the tea che r.She smiled—and stood back. Sp eaking to a room full of sc i en t ists is one thing. Standing before a class of ki d s — wh et h e r kinderga r tne rs or high- s ch o ol seni o rs—is some thing els e . Wit h ki d s , Q-and-A isn’t just an after-talk interva l ,i t’s a way of li fe . If you have an hour to share with a cla s s ,h o w can you make the time cou n t ? Aft er plent y oftria l - a n d - e rror,sc i en c e educ a t ors and savvy volu n t eers have some ha rd - e a rn e d tips to off er.“Talking to kids can be a great boost for any scien- tis t , ”sa ys Nancy Moreno ,he a d ofthe hh m i -f u n d ed Scienc e Educ a ti o n Lea d- ership Fello ws Program (sel f ) at Baylo r Coll e ge of Medicine in Hou s t on. “And these are skills you can learn. ”

✎Tip 1: Kn o w Your Aud i e n c e To give a great talk,stu d y up on your stud ent s . You could proba b ly guess

Rohit Var m a ’ s skel e ton drew a flurry of unexp e c ted that fou r th graders aren’t rea dy to run gels — b ut did you know that even qu e s tions in his son ’s kinderga r ten class. eig hth graders have a hard time grasping the comp l ex i t ies of dn a?

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Sc i en t ists oft en overes ti m a t e a cla s s ’s gene ral sophi s ti c a ti on . Dur ing one recent proje ct, for instance, Moreno and coll e a g u e s develo ped lesson plans for elem en t a ry - s ch o ol stud ent s . The y were partic u l a r ly pleased with a model that used different kinds of popcorn— b utt er, che ese and cara m el — to show that air is a mix of gas e s , with each vari e ty repres en t ing a different gas . The tea che rs who used the model reported that the kids were cer- ta i n l y fascinated, but some took home an unexp ected lesson. “M ost of the first - g rade chi l d r en conf i d ent l y reported that air was made out of popcorn, ” Moreno says. “You have to learn to be so hum bl e . ” So before you painstakingly mold ras p berry Jell-O into a replica of a cell memb ra n e ,m a ke a pho ne call. “The tea che r kn o ws the stud ents bes t , ” sa ys Laura Streich e rt ,h e ad of th e spe a k er’ s bur eau at the Was h i n g t on Ass oc i a ti o n for Biom e d- ical Res e a r ch in Sea t t l e .“ I f you make the tea che r your part- ne r,your talk has a muc h bett er cha n c e of hi t t ing the target. ” Res e a r che rs can che ck out the Nati o nal Scienc e Edu- ca ti o n Standards to see wha t ’s typi c a l ly taught at each grade le vel. Keep in mind, ho wever, that the standards are gen- eral bench m a r ks—and scho ols var y wid ely in meetin g th em .“ E ven if you take third or fou r th grade as your level and gear you r talk to that,it wil l not be universa l ly underst a n d a b le to kids of that age, ” Na n c y Moreno says rese a rc h e r s can pick c a uti ons Jon Levi t t , a po s tdoctoral fell ow in the Dep a rtm ent of up the skills needed to talk to kids about sci e n c e . Immu n o l o gy at Baylo r Coll e ge of Medicine and a freque nt grade- sch o ol vis i t or. “The re’s a big differenc e betw een schoo l s , pa r tic u l a r ly sa ys, “but most of th e m think it’s rea l ly cool . ” those with stud ents from different soci o econo mic backg rou n d s . ”Agai n , Even simple props can jazz up a talk.What does the brain do? To a tea cher ’ s insight is key. ta ckle this que s ti on , Chudl e r jug gles plastic brains while he leads the kids throu g h a guessing game on mus c le coordi n a ti on , ba l a n c e and ✎ Tip 2: Bring Prop s si gh t . What is the brain made of? For this on e ,s tu dents become a gia n t When e ver David Schn ei d er, a molecular bio l o gist at the Whi t ehe a d neu r on ,l i n ked to each other with rope ,p l a s tic and ping-pong balls . Ins ti t ute for Biom e dical Res e a r ch in Cam b rid ge , Mas s a chus et t s , cli m b s Whe n Levitt tea ches abou t fric tion , he asks stud ents to pull a chi l d the steps to a local grade schoo l , he brin g s along ext ra vis i t ors: bu gs . in a wagon with—and then wit h o ut — s a n d p a p er beneath the whe els . “I call them ‘ext reme insects , ’”Sch n ei d er says. “Sc a r y one s , hug e one s , The same approach works with older crowds . High - s ch o ol kids rea l ly bea u tiful one s . ”Sh o pping the Int ernet ,S ch n ei d er buys drie d bee- don’t play with wagons , but they usua l ly do like exp erim en t ing with the tles and butt erflies for kids to hold.“I t’s a way of breaking into bug bio l - qui ck - f r eez e properties of li q uid nitrogen ,w a tching flowers crum bl e ogy,”he says, and it work s .“ I ’ve been amazed by how qui ck l y you n g or pennies shatter after a dip in the stuf f . “Skip the PowerP oint pre- kids can pick things up. They ’ re curious abou t everyth i n g .” sen t a ti on s , ”advises Mar y Mar ga r et Welch , a bio l o gy tea che r at Mercer Ali ve or dead , real or pretend , props are a great way to rea ch kids. Island Hig h Scho ol in Was h i n g t on .“ Bring some thing to do instead . ” Just ask Eric Chu dl er, a neuro s c i en t ist at the Uni versi t y of Was h i n g - ton in Sea t t l e , who has been volu n t eering mont h l y at local scho ols for ✎ Tip 3: Li g h t en Up abo u t five ye a rs . By now, he ’s got props down to, well, a science . No matter what gizmos you may bring in your backp a ck, volu n t eers Chudl e r brin g s in six ja rs ,e ach holding the brain of a different ani- sa y,come to a cla s s r oom with the rig ht atti tu de .“ Kids can rea l ly sens e m a l ,f rom a cow to a cat. He des c ri b es the differenc es—in brain size whet h e r or not you are into what you are doin g , and they wil l imme- and patterns of fol d s , for instance— b etw een speci e s , and then asks di a t ely pick up on your vibe s , ”sa ys Har ry Orf ,d i rector of Har var d Uni - kids to ident ify the brain in each jar .“Some kids say it’s gros s , ”Chudl e r versi ty ’ s molecular bio l o gy labs at Mas s a chus e tts Gene ral Hos p i t a l .“ I f

Di f fe r ent Strok es for Differ ent Age s

G RA D E-SCHOOL KIDS M I D D L E-SCHOOL KIDS H IG H -SCHOOL KIDS ✏ Li k e natu r e ✏ Un d e r s tand eth i c s ✏ Ide n t i f y with peers ✏ Ide n t i f y with fam i l y ✏ Challenge rules ✏ Qu e s tion authority ✏ Worry about fai r n e s s ✏ Think in the abstra c t ✏ Can inter p r et complex science ✏ Ge t exci t ed easily ✏ Become self-conscious ✏ Consider caree r s ✏ Need frequent physical activity ✏ Need positive rei n fo rc e m e n t ✏ Need to be inspired

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you ’re tent a t ive ,t h ey ’ ll be tent a t ive. If you ’re having fun, so wil l they.” Amo ng you n g er crowds , in partic u l a r , ent h usiasm is cont a gi o u s . “All Cl a s s r oom and Online Edu c a tion Reso u rc e s it takes for a young child to get interes t ed in scienc e is some sort of sp e- Some scientists go back to school themselves befor e stepping foo t cial momen t , ”Var ma says .“ Kids want to be baseba l l players because we in a classroom full of children. At the Univer s i t y of California, San pa y so muc h attenti o n to them. The y don’t see a whole lot of exci t emen t Francisco, more than 150 scientists have completed six hours of in science , but there’s a real thril l in discovering some thing new—and it’s Sc i e n t i s t Orientation Wor k shops, part of an HH M I- s u p p o r te d easy to share. ” school outreach prog r am there. Sever al Web sites off er infor m at i o n Even at the middle - s ch o ol level, kids can oft en overcome their inhi- for scientists intere s ted in speaking to schools: biti o ns and rea l ly enj o y learning abou t scienc e from a stran g er.“Mi d dl e - sch o ol stud ents stil l tend to have lots of ent hu s i a s m , and they’ re oft en wil l- ✏Un i ve r s i t y of California, San Francisco, Science and Health ing to accept you just on face valu e , ”sa ys Larry Ann Ott , a bio l o gy tea che r Edu c a tion Par t n e r s h i p at Northglenn Hig h Scho ol in Denver.“The ir emo ti o ns are close to the sur - www.u c s f.ed u / sep / i n d ex . h t m l fa ce. ”High - s ch o ol stud ent s , Ott says, requi r e a different tou ch . “Old er stu- ✏ Res o u r ces for Involving Scientists in Edu c a tion (RIS E ) dents have been throu g h a lot more, and they tend to be more cynical or www.n a s .ed u /r i se / sub du ed , ” sa ys Ot t .“ It takes more to captur e their imagin a ti on . ” ✏Sharing Science with Children: A Survival Guide for One solution , Ott says, is to keep the scienc e rele van t . High - s ch o ol stu- Sc i e n t i s ts and Engineers dents get swept up into social conf l i ct s , with cha n g ing fri en d s h i p s ,d a t- www.n o a o .e d u /e d u c a t i o n / tgu i d e s /sci t xt. h t m l ing and plans for the futu re .“ If you can bring any of th i s — g end er dif- ✏ HH M I ’ s Precollege Science Edu c a tion Prog ra m ference s , so cial interaction s — i n t o your discussion, it can make a major www.h h m i .o rg /g ra n t s/pre c o l l e g e / di f f erenc e in what they remem b er,” Ott says. Cat ch their atten ti on ,a n d th e ir curio s i t y wil l foll o w. ✎ Tip 4: Ge t Movi n g At meeti n gs ,s c i en tists oft en listen to 50-minute lecture s . At sch oo l , 50 minutes is an eterni t y. Kids move around a lot. If you want to keep their attenti on , get mov- in g , too.“The more you move arou n d , the more they have to keep watching you , ” Levitt says. “Wha t ever you do,don’t stand at a lectern and rave on. ”A couple of yea r s ag o, Levitt was five minutes into his first talk to a grade- s ch o ol class whe n he rea l - iz ed that nothing was sinking in. Kids were elb owing each other, lo oking arou n d , pl a ying with their sneakers. He qui ck l y jum p ed up to cha n g e gea r s—and he hasn’t st opped moving since. I f David Schneider uses “extr eme insec ts” to spark y o u’ r e ch i l d re n ’s curiosi t y about bug biology. m ovi n g a ro u n d , and the kids get a t u r n h a n - d l i n g prop s , wh a t’s t h e

H

te ach er doing? Try i n cluding him or her, Moreno advi s e s . h h m i b u l l e t i n | s e p t e m b e r 2 0 0 1 21 Sc i en c e looks easier if a familiar perso n can do it,too.“I f we pu t a tea che r up there in front of the kids, si d e by side with a res e a r che r, we se nd a message that scienc e is approacha bl e , ” Moreno says. “Tha t ’s an importa n t me s s a ge . ” Wha t ’s more ,S ch n ei der add s , the tea che r can keep kids on task.“With the lit- tl e r kids, in partic u l a r , I just don’t have the skills to cont rol them, ”he says ruef u l ly. “I wou l d n ’t want to go in co l d ,a l on e . It’s important to have the tea che r close by.” ✎ Tip 5: Fol l o w Up Sp ending an hour with a class can bring smiles all arou n d — b ut foll o wing up can do even more. Tea che rs may build on your talk,doing lessons afterwa r d to rein f orce wha t ever you ’ve taught . Cha n c es are, th e y wil l also have qu e s ti ons along the way. “I f you rea l ly want to make a differen ce ,m a ke a comm i tm en t , ” sa ys Keith Verne r, chi e f of the divis i o n of develo pme ntal pedi a t rics and learning at Penn s y lvan i a St a t e Uni versi t y Coll e ge of Med i c i n e .“ Don’t wait to hear back from the tea che r. In s te ad ,s end an e-mail. Say,‘H ey, I enj o yed that. Have any que s ti o ns come up that I could answer? ’ ” Man y tea che rs would welc ome the input. “A real partne r is not just abou t hav- ing some one come in and give this pres en t a ti on , but having some one who ’s wil l- ing to be on call, ”sa ys Wel ch .“ It’s some one I can call if th e re’s a kid who got rea l ly exci t ed by some thing or had a qu e s ti on I cou l d n ’t answer. Tha t ’s the kind of pa r t- ne rship we need. ” That sort of pa r tne rship is not very hard to crea te , adds Har vey Lodi s h , a molec- ular bio l o gist at the Whi t ehe a d Ins ti t ute. “All res e a r ch instit utes can do somet h i n g .” Maybe a scient ist can give one talk a year to third graders, or make a special pres en t a - tio n to high- s ch o ol stud ent s . “We can’t cha n g e the world , but we can cha n g e a little pi e ce of it . ” LearnOnline.Final 10/9/01 9:42 PM Page 22

CO L L E GE STUDENT ME E TS EL E CTRO N MA N Initial panic turns to insight as students embrace online learning. BY M. MITCHELL WA L D RO P

is students tend to freak out at first, the most fundamental principles of sc i en c e—that hypotheses have to sa ys Pres l e y Mar tin , de s c ri bing the introduc tory bio l - be tes t ed ,a l terna t ives have to be rul e d out, obje ctio ns have to be satis - ogy cou r se he tea ches at Hamline Uni versi t y in St. fi e d and a conc lus i o n requi r es evid en c e.“Ask for sup portive evid ence , ” Pau l , Min n e s o t a . Whe n they walk into the cou rs e ’s lab- sa ys Mar tin , “and at first they’ re just puzzled. ”As the exercises progres s , orat ory sectio n for the first tim e , the stud ents find ho wever, at least some of the stud ents rea l ly do begin to get it. t h em s elves face - to - s c reen with the Gen etics Con- St ories like Mar tin ’s are being heard more and more oft en. Tha n k s s tru cti on Kit (g ck)—a com p uter simu l a ti on of to the prol i f erati o n of hi gh - p owered perso nal comp u ters on campus HMend elian inherit a n c e that wil l comp el them to do some real science . and the rapid growth of the Int ernet , coll e ges and universi t ies are exp er- To begin an exp erim en t , the gc k gene rat es a “fi e ld coll e ctio n”of ,s ay, im en t ing with comp u ter-b a s e d learning as never before— f r equen t l y fr uit flies, ea ch with a combi n a ti o n of trai t s — wh i t e eyes or red eyes , bent with bio l o gists among the leaders. Ind eed, ma n y of those bio l o gis t s win g s or stub by win g s or strai g ht win g s and so on. The program also pro- beli e ve that online learning is the best hope for maintaining high- qu a l - vid es the tools for performing gene tic cro s s e s ,p lus a spread s h e et to ana- it y,in d i vidu a l i z ed educ a ti o n in the face of un d erg radua t e enro ll m e nts that lyz e the outcomes statis ti c a l ly.It does no texplain the hidden gene tic mech- ha ve sur g ed dram a ti c a l ly dur ing the past deca de. Some bio l o gy educ a - anisms that produc ed those outcome s . Nor does it off er a tradi ti o nal lab tors would use online sources to help cha n g e the meth o d of le a r ning itself , ma n ual that tells the stud ent how to find out. Ins te ad , the stud ent is exp ect- regar dless of class size. The y find that the gc k and similar soft w a r e pro- ed to deci d e what traits to look at, what crosses to try,what hypotheses to grams can be powerful tools for giving stud ents an exp erien c e as close as cons i d er and,perhaps most importa n t , whe n to be satis f i e d that a hypot h - pos s i b le to real scient ific res e a r ch— w hat curric u l um reforme rs call esis is correct, just as a scient ist faced with a real field coll e ctio n must do. “i n qu i ry - b a s ed ”l e a rn i n g .Stu d ents are enco u ra g ed to ask their own que s - “They ’ re rea l ly uncomf orta bl e , ”sa ys Mar tin , who is cha i r man of th e ti on s ,s trug gle towa r d the answers and, in eff ect, tea ch thems e lves . Hamline bio l o gy depa r tmen t . “They ’ re used to proble ms whe re they’ re exp ected to get the ‘rig ht answer,’so it’s hard for them to deal with the RA ISING SKILLS AND EX P ECTAT IONS fa ct that the program isn’t going to tell them whe n they get the righ t Certa i n l y that was the intent of the kit’s co- c re a t or, bio l o gist John R. an s w er.” Ins te a d it conf r onts them with the task of le a r ning first h a n d Jun g c k of Belo it Coll e ge in Wis c ons i n , who wrot e the program in 1985

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Michigan Stat e’s Joh n Merrill uses online animations and comic- book charac ter s to draw stu d e n t s into first-yea r bi o l o g y . A hamburge r with fries makes sen s e out of proteins and fat s. A superhero dubbed El e ct r on Man “protec ts” cellular res p i r ation.

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with bio l o gist John N. Call e y, th e n at the Uni versi t y of Ariz ona . In a 1988 John Jungck of Bel o i t ar ticl e , Jun g c k and Nils S. Peterso n College designed the of Wa s h i n g ton State Un ivers i ty Ge n e tics Constr u c tion Kit and other computer- b a se d exp l a i n e d that the tea ching and the learning modules to help col- sof t w a r e work togeth e r to rein f orce lege stu d e n t s learn to the “3 Ps” of res e a r ch: problem - po s - become effect i v e prob l e m in g , problem - s o l ving and peer per- sol ve r s. An o ther prog ra m , sua s i o n—the peers in this case bein g called BIR D D , shown below, the other stud ent s . de s cribes the impact of That 3-Ps approach has, in turn , Ga l p a g o s finches on been the guiding principle of t h e Charles Darwin's rese a r ch. Bi o QUEST con s ortiu m , wh i ch Jun g c k and a group of li ke - m i n d ed s of t w a re aut h ors fo u n ded in 1986. The cons o rtium , whi c h is loca t ed at Belo it Coll e ge and funded partl y wit h hh m i gran t s , maintains a librar y of so me 70 too l s ,s i mu l a ti on s , da t a b a s - es and other res o u r ces develo ped for un d erg radua t e bio l o gy.Ea ch res o u r ce is peer- revi ewed , ava i l a ble on cd - rom and enh a n c ed by data read i l y retrie ved from the Int ern et . Amon g the off erin g s are the orig inal Gene t- ics Cons t ruc tio n Kit , Sequen c e It! (a simul a t ed prot ein - s e quen c i n g hypo t h e s e s ,s h a ring data. A te ach er in one of our work s h ops told me lab) and bird d —Be a g le Inves ti ga ti o n Retur ns with Darwinian Data recen t ly that their worst proj ect this year is bet ter than their be s t (a tool for exp l o ring evol utio n throu g h a database of ta x ono my, son g proj ect three ye a rs ago. An o t h er said, ‘ we never knew our stu den t s recordi n gs , dn a se quen c es and measur eme nts on some 650 speci m en s were that cre a tive.’ ” of Ga l á p a g os finche s ) . He admits that this kind of s c i en ce te aching is never going to be Ju n g ck is espec i a lly taken with how su ch too l s , com p l em en ted as easy as the trad i ti onal approach , In tern et or no In tern et . “ For by e-mail, d i s c u s s i on groups and chat room s , h ave ra i s ed the skill s te ach ers , i t’s more inten s e ,” he says . “With oodles of proj ects goi n g and ex pect a ti ons of s tu dents to a whole new level . “You see them on all the ti m e , and with stu dents accessing all these com p l ex too l s , en ga ged in co ll a bora tive probl em - s o lvi n g, l ooking at mu l ti p l e you have to be wi lling to let the stu dents te ach you things . And that’s

being de s i gn ed at Stanford to give large “H a n d s- O n ” Ren a l introductory physiology classes hands-on, lab-like experiences without going to a lab. Ph ysi o l o g y Other virtual labs will focus on human gas- troin te s ti n a l ,c a rd i o vas c u l a r , res p i ra t ory and How well can physi o l o gy stud ents underst a n d neurobiological systems. an y of the human body’ s three- d i m en s i on a l , “This is more than a digital text book , ” dynamic syst ems whe n they are conf i n e d to s ays Ca m i llan Hu a n g, vi rtual labs proj ect le a r ning abou t them from lecture s , text book s m a n a ger. “ It is fun, and it helps stu den t s and flat, st a t ic pictur es? At Stanford Uni versi - un d erstand difficult conc epts and rela t e wha t ty, stu d ents can take an active and more rea l - th e y are learning to their everyda y lives . ”In a is t ic add i ti o nal step: The y can log on to the Stu d e n t s can dilate or constr i c t arterioles of the preli m i n a r y comp a ri s o n of stu d ent achi e ve- hh m i Vir tual Laborat ories and stud y rena l ki d n e y and see the impact on glomerular filtrat i o n . men t ,s tu d ents who used the vir tual lab scored physi o l o gy by manipulating the diameters of hi gh e r than those who onl y attend ed lecture s ca r toon arterio l e s — m i n ute bran c hes of ar ter- tip l i e r actua l ly affects the conc ent rati o n of sod i - and rea d the text , Huang reports . ies in the kidney— t o see the cha n g es in filtra- um , chl o rid e and pot a s s i um as liquid moves —JENNIFER BOETH DONOVA N tio n rate s . The n they can simul a t e urin a l ysis on th ro u g h the tub ules of the kidney. fi ve “pa ti en t s ”and see how a daunting mathe- The renal physiology lab, supported by »Mor e inform a t ion and demo n s t rat ion labs can be ma t ical conc ept calle d the cou n t ercu r rent mul - an hh m i gran t , is the first of fi ve vir tual labs found online at: sum m i t . s t a n f ord. e du/ h h m i /

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a hu ge ch a n ge in the social con tract of the cl a s s room .” Mea n whi l e , Jun g c k says, “for the stud ents this is a lot more work than just passively sitting in front of an instruc tor, taking notes . But even Lap tops Link Chemistry so , fr om all of our stud i e s , the stud ents who go throu g h this proces s retain more. The y stay in the cou r ses long er.The y more oft en go on and Students and Teac h e r s ta k e add i ti o nal scienc e cou rs e s . The y are bett er at appl ying what they’ ve U.S . Pres i d ent James A .G a rf i eld onc e said that the ideal coll e ge le a rn e d to social and legal issue s . And they seem to have a conversa n t , consists of a profes s o r on one end of a log and a stud ent on the sp eaking knowl ed ge of sc i en c e for a long time after they finish.” ot h e r end . A netw ork of 16 iBook laptop comp u ters is putti n g chem i s t ry stud ents and facu l t y at Deni s o n Uni versi t y in Gran vill e , F I RST-Y EAR BIO LO GY ONLINE Oh i o , on “the same log” in a way that Garfi e ld could not have None of the sof t w a re in the Bi o QUEST libra ry was spec i f i c a lly im a gi n e d in 1881. de s i gn ed to help te ach ers cope with overc rowded cl a s s e s , but that is Wir eless and mobil e , the laptops move easily from cla s s - def i n i tely an issue at Mi ch i gan State Un ivers i ty, wh ere an interd i s c i- rooms to laborat ories throu gh o u t the chem i s t ry depa r tmen t ’s p l i n a ry team of bi o l ogists and edu c a ti on specialists is attem pting to tw o bui l d i n gs . Bio chem i s t ry stud ents use the netw orked com- p ut the sch oo l ’s en ti re firs t - year bi o l ogy curri c u lum on l i n e . Af ter all , pu ters to do rea l - t ime data analysi s , record assay data,tran s f orm n o tes microbi o l ogist John Merri ll , one of the leaders in that ef fort , and plot data points and test the devia ti o n of coll e cted data from “unless the state su d den ly throws a hu ge amount of m on ey at us so exp ected valu e s . The y also can access and manipulate a prot ein that we can have everybody in small cl a s s e s , I sti ll have to te ach these st ruc tur e database dur ing cla s s , with the profes s o r on hand to hu ge co u rses with 400 stu den t s .” he lp them over hur dle s . Stu d ents in gene ral chem i s t ry learn to The proje ct ,c a ll ed “F i r st Year Online,”began in 1998 as part of a five- use a spread s h e et for data proces s i n g , st a ti s t ical analysi s , grap h- yea r ,$1.6 milli o n grant from hh m i ,sa ys proje ct director Estelle McG roar - ing and linear regres s i on . A spectros c opy database and soft w a r e ty,and it soon proved to be an even more daunting task than the team had for analyzing nuc lear magne tic res on a n c e spectra bring comp l e x im a gi n ed .“ I t took us most of a year after we were funded just to figure out conc epts to life at every org anic chem i s t ry lab bench . ho w to approach online bio l o gy,”she says.“ E a r ly on, for exa m p l e , we made Sup ported by an hh m i gran t , the chem i s t ry depa r tmen t ’s the deci s i o n that we would not provid e a comp l e te vir tual cou rs e . Bio l o - la p top netw ork has inspired Deni s o n’s bio l o gy depa r tme nt to gi s t s ,m ore so than the physi c i s t s , feel that there has to be a face- to - f a ce cre a t e a wir eless laptop comp u ter netw ork of its own ,s ch edul e d comp one nt in tea chi n g .” for use dur ing the 2001–2002 aca demic yea r . —J B D Mat erials are pres en t ed using lo l , the Lectur e Online platform that ha d just been develo ped at Mich i g an State by physics res e a r ch associ - at e Gerd Korteme yer. Li k e comm e rcial cou rs e - m a n a g eme nt soft w a re , ant to the First Year Online project. “You can tell them, tell them and lo l off ers tools for keeping track of adm i n i s t rat ive details suc h as tell them again—and if th e y have a different mental model ,t h ey won’t enro ll m e nt and grade s ,a n d , most importa n t l y, it allo ws instruc tors to get it. Most incoming freshmen think that only animals respire; they cu s t omi z e the online cont ent to suit their particular needs . h ave tro u ble with the con cept that plants do too. Th ey think that plants get their food from the soil , and forg et that there’s this stu f fc a ll ed H OW TO HELP STU D E N TS LEA R N carbon dioxide in the air. In fact,the whole notion of the carbon cycle “The re is a prett y strong body of evid enc e that stud ents don’t learn and its con n ecti on to gl obal warming is a hard con cept . So in the muc h by just being told abo u t science , as in being lectur ed to, or jus t hhmi project we try to give them modules on concepts that we know rea ding abou t it,”sa ys team memb er Joyce Par ker of the divis i o n of sc i - are hard to understand.” enc e and mathema t ics educ a ti on . “The y first have to be enga g ed in some Ulti m a t ely, the proje ct’s goal is to produc e 20 to 30 suc h modul e s so rt of problem , so that they can see a purpos e : ‘H ere’s somet h i n g covering the cont ent found in most introduc tory bio l o gy text book s . In in t rig u i n g , le t’s try to understand it.’” develo ping the modules intend ed for the first seme s t er of in t roduc to- The online modules are des i gn e d to start by piquing the stud ent s ’ ry bio l o gy (“Cells and Mol ec u l e s” ) , Merril l says, the group has been in t eres t — s om e times prett y shamele s s l y.Ph o to s y n t h e s i s , for ex a m p l e ,i s le a r ning a lot of le s s on s . “One is that develo ping online educ a ti on a l pres en t ed as an animated play in eig ht acts , with the water molecu l e ma t erials is a hug e underta k i n g . In the way that we’ve done it, it ’s a lot an t h r opomo rphi z ed as a trag ic hero who sacri f i c es himself for the good li k e writ ing a text book—and I don’t think we were prepa r ed to writ e a of the cell. Cellular res p i ra ti o n and the ele ctron tran s p ort chain are pre- text boo k .P lus it requi r es all the same skills as develo ping a comp l e x Web sen t ed in comi c - b ook style , comp l e te with a caped crus a der:“The Story pa ge . It’s qui t e a cha ll en g e for a facu l t y memb er to learn the graph i c a l of El e ctron Man . ” des i g n tools you need for that.” “We use what works , ” la u g hs Merrill , who partic u l a r ly enj o ys the A second lesson ,s ays Merrill , is that online tea ching is rea l ly an art la r g e biom o l e cules modul e . “We start each sub topic with a pictur e of a form. “The best pieces we’ve produc ed have an individ ual voic e and sen- ni c e juicy hambur g er with a side of Frenc h frie s , and then we have si bi l i t y.”The re’s no formula for that,he says, “except to recogni z e it whe n ar rows poin t ing to, sa y, prot ein in the meat.” it happens . ” H Once you’ve got the students’ attention,then what? “The student has to wrestle with the materia l , ”sa ys plant ecol o gist Diane Ebert- M ay, » For more inform a t ion on BioQUE S T , visit: bio que s t . or g / di r ector of Mich i g an State’s Lyman Brig gs Scho ol—a res i d ent ial com- » For more inform a t ion on MSU’s Fir st Year Online Project , vis i t : munity for students in the natural sciences—and a frequent consult- le ctu re . l i te .m su . edu/ ~ bi o / f yo l /

h h m i b u ll e t i n | s e p t e m b e r 2 0 0 1 25 PERSPECTIVE Repairing the Disconnect Between Research and Teaching By Peter J. Bruns

ane just started her freshman year at a top- each other in provocative ways. Science education ranked state university. John is a freshman at an must involve more than facts and concepts; students Ivy League school. Both were outstanding high- need to learn how we do research and be exposed school students interested in pursuing careers in enough to the excitement of discovery to be Jscience and medicine, so they chose those insti- inspired to learn more about science. In a world tutions precisely because of their reputations for increasingly dominated by science and technology, research excellence. even those who will not become science majors John and Jane may be in for a shock. They could need to learn enough about the content and process find themselves in packed lecture halls, listening to of science to be informed decision-makers and

instructors who would rather be almost anywhere FETTERS PAUL rational, critical thinkers throughout their lives. else. Their labs and seminars may be taught by grad- Research scientists and their institutions some- uate students who often are doing it not for the love of teaching, times say that teaching takes valuable time and attention away from but to pay for their Ph.D.s. Meanwhile, the research leaders with research, but this is a short-sighted view. Teaching adds value to whom John and Jane hoped to study may be tucked away in their research by providing the fresh insights that flow from creative labs, supervising their research teams, writing grants and avoiding interaction among undergraduates, graduate students, postdoctoral undergraduates whenever possible. fellows and senior scientists. It also provides apprenticeship experi- Unfortunately, we have evolved a built-in disconnect between ences in science education for graduate students and postdoctoral research and teaching at many of our biggest and best universities. fellows—the scientist-educators of the future. While undergraduates go to In my years at Cornell, I research institutions to get an watched with joy as undergrad- outstanding baccalaureate uates became fully integrated education, the faculty at those A Novel Initiative: in my research group and those same universities seek (and The HHMI Professors Program of many of my colleagues. need) to do cutting-edge WHAT’S NEW? These awards will be the first undergraduate bio- They clearly brought fresh research that often depends logical sciences education grants ever made by hhmi to individuals. ideas and wonderfully chal- on peer-reviewed funding. To lenging, if naïve, questions to move important research for- PURPOSE To overcome the traditional “research vs. teaching” lab meetings and daily interac- ward, faculty attention is dichotomy by encouraging successful research scientists to devote tions. Still, individual research diverted from local teaching time and creativity to undergraduate teaching. projects by the top few stu- needs to a sometimes over- INSTITUTIONAL BASE Eighty-four research and doctoral uni- dents at research universities, whelming concern about the versities have been invited to nominate up to two professors, who although desirable, are not attitudes of review panels in will submit proposals for innovative undergraduate teaching pro- enough. The synergy of Washington. Although faculty grams that build on the strengths of their research and teaching. research and teaching needs to value and for the most part extend beyond the few and be NOMINEE QUALIFICATIONS Individuals appointed as hhmi enjoy teaching, it is research part of the standard fabric of professors will be recognized biomedical research leaders who that tends to yield the rewards science education in research also have demonstrated teaching ability and would like to do of tenure, rank and pay—in universities. more in undergraduate education while continuing their research. other words, professional In that spirit, hhmi has A panel of scientists and educators will review the nominees’ respect—while teaching usu- launched a new initiative to research, teaching performance and proposals. ally winds up low on the help bridge the gap between totem pole. HOW MANY AND HOW MUCH? Twenty hhmi professors will lab and classroom. The Yet good research and be chosen; each will receive a four-year award totaling $1 million. Institute has committed $20 teaching can coexist, and actu- million to support 20 “hhmi WHEN? The awards will be announced in September 2002. ally reinforce and invigorate Professors” for four years at

26 hhmi bulletin | september 2001 SAL SAL DIMARCO JR./THE NEW TIMES YORK research universities across the nation. The program’s goal is simple: undergraduates, and an ardent desire to try out these ideas. to encourage faculty members who are very creative scientists to In the tradition of hhmi’s appointment of investigators, the apply some of that creativity to undergraduate education. awards to hhmi Professors will support promising individuals The hhmi Professors program is designed to legitimize and rather than projects; the awardees will be given the freedom to try reward great teaching, encouraging science departments at research innovative ideas, which includes the liberty to change direction. We institutions to place a higher value on undergraduate teaching. By hope to empower imaginative people to direct their skills and ener- supporting the development of innovative, crossdisciplinary and gies to undergraduate science teaching, and then share the results. multiyear lab courses, the Institute hopes to enhance the alliance The baseline for this experiment is not zero. I certainly have col- between research and education and to generate new undergraduate leagues all over the nation who have worked hard to bring innova- curriculum materials that can serve the entire science community. tive science education to undergraduates. But no individual or cam- At hhmi, a gap has tended to separate investigators who con- pus in isolation can change the center of gravity on this issue. The duct research in universities and medical centers from their peers National Science Foundation has just begun a distinguished teaching who receive support through the Institute’s science education grants scholars program and the Carnegie Foundation for the Advance- programs. I hope that by participating in both research and science- ment of Teaching is supporting initiatives such as Portland State education meetings at the Institute, the hhmi professors will cre- University’s Center for Academic Excellence. We hope that putting ate synergy between those groups, a goal to which the Institute’s the hhmi imprimatur on scientist-educator programs will further leadership is committed. stimulate a cascade effect, motivating more science departments and Nominations for hhmi professors have been invited from 84 their institutions to seek out and reward good undergraduate teach- institutions and will be selected by an expert panel of scientists and ing. In any case, it will help form the beginnings of a cadre of scien- educators. Nominees will each have a proven track record in tist-educators that can be instrumental in improving the quality of research, as well as some teaching experience. They will also have undergraduate science education for generations to come. H two other assets of special importance: innovative ideas on how to change the fundamental ways in which science is presented to Peter Bruns is hhmi’s vice president for grants and special programs.

hhmi bulletin | september 2001 27 NEWS& NOTES

The Hidden World of Membrane Proteins

n entire class of proteins has long phase proves to be limited, I expect that fast friends and colleagues in 1998 when resisted the best efforts of scientists what he learns about how membrane pro- Navarro, a clean-cut and high-spirited native Ato fathom its mysteries. These mol- teins interact with lipids will be highly of Peru, took a year-long sabbatical at the ecules—known as membrane proteins instructive.” lab Landau was running at the University of because they reside within the fatty mem- In August, Landau and colleagues pub- Basel in Switzerland. branes that encase the body’s cells (and cer- lished the molecular architecture of a sec- Landau and his collaborator, Jurg tain internal parts of cells)—are involved in ond bacterial membrane protein, called sen- Rosenbusch, a pioneer in membrane-pro- a vast range of vital functions. They regu- sory rhodopsin II. Discerning its structure is tein research, had recently developed a late the flow of nutrients into cells, let waste important, says coauthor Javier Navarro, novel concept to stabilize membrane pro- products out and relay messages that sup- because “this bacterial protein is structurally teins in three-dimensional bilayers—the port life or trigger cell death. By chaperon- and functionally related to a family of use of the “lipidic cubic phase.”Navarro, ing microbes into cells or by failing to func- G protein-coupled receptors,”which, he who, like Rosenbusch, knew the evasive tion properly, membrane proteins can also notes, are the targets of some “60 percent of play a role in making us sick. They are basic all drugs currently in use.”Knowing the Ehud Landau (left) and Javier Navarro have set out to the improved understanding and treat- structure of sensory rhodopsin II brings the to solve the structures of membrane proteins by ment of depression, Alzheimer’s disease, researchers closer to understanding the recreating the molecules’ native environs. cystic fibrosis, blindness, childhood diar- G protein-coupled receptors, some of which rhea and a host of infectious diseases. mediate sight, smell, neurotransmission and Despite their obvious importance, the body’s recognition of the human fewer than 30 of the estimated 20,000 immunodeficiency virus. membrane proteins that exist have been Even with the excitement of determin- described structurally—atom by atom. ing this new structure, Navarro admits that They are notoriously difficult to purify and the road is slow going. “We’re working to crystallize. crystallize 15 membrane proteins right The University of Texas Medical now,”he says, including some G-protein Branch at Galveston (utmb) has imported coupled receptors and a protein involved in a possible solution from Europe, along with cystic fibrosis. “If we get one a year, that its codeveloper, Ehud Landau. He’s devised would be fantastic.” a way to quickly remove the proteins from Landau and Navarro are codirectors of their stable lipid-layered environment, utmb’s Membrane Protein Laboratory— purify them and insert them into a new one of three core facilities of a comprehen- material that imitates their native milieu. sive new program built with support from The proteins remain stable enough to crys- an hhmi grant designed to help medical tallize, which is a prerequisite for solving schools build facilities, hire faculty and cre- their structures by using x-ray crystallogra- ate centers of excellence. The other core phy. Landau and colleagues first used this labs are devoted to the genetics of mem- concept, the lipidic cubic phase, to crystal- brane proteins and the development of lize a membrane protein found in bacteria small molecules designed to activate or called bacteriorhodopsin in 1997. inhibit the function of these proteins. “It is terrific to see Ehud following up With a thick beard and horn-rimmed on his stunning success in bacteri- glasses, Landau exudes an intense scientific orhodopsin crystallization with tests on work ethic. The Israeli researcher spent years other membrane proteins,”says hhmi as a physical chemist studying the nuances investigator Wayne Hendrickson, a struc- of how lipids—the main components of cel- tural biologist at Columbia University. lular membranes—behave under different

“Even if the applicability of lipidic cubic conditions. Landau and Navarro became JOHN GLOWCZWSKI

28 hhmi bulletin | september 2001 behavior of membrane proteins, was eager detailed, three-dimensional images of the Bacteriorhodopsin turns light into cellular to learn the new technique. molecules. For decades researchers have energy, making it nature’s simplest photo- The lipidic cubic phase stood out been growing nonmembrane proteins into synthetic machine. because it promised to speed the pace of well-ordered networks, or crystals, that can Henderson’s structure was ground- research in a field in which progress had then be bombarded with x-rays. The result- breaking—but crude by present-day stan- been terribly slow, mainly for two technical ing diffraction patterns are analyzed to pro- dards because it showed only the protein’s reasons. First, unlike other proteins, those duce pictures of the molecules’ architec- general folding pattern. Scientists prefer the residing within fatty layers of cellular mem- ture. It’s tough to crystallize membrane ultimate insight: an atom-by-atom picture brane don’t dissolve in water. When proteins, however, because this process, like of the molecule. No one succeeded until researchers try to purify them—separate purification, relies on detergents. Unfortu- Landau and Rosenbusch, together with the proteins from their membranes—the nately, “what works for one doesn’t [neces- French crystallographer Eva Pebay-Pey- water-loathing, fat-loving layers of the sarily] work for the other,”says Navarro. roula, published their structure of bacteri- membrane uncoil, gelling into a useless Researchers, he says, often have to screen orhodopsin in Science magazine 22 years mass like the white of a hard-boiled egg. To many detergents and settle in the end for later, in 1997. overcome this problem, researchers tradi- less than optimal results. Landau and Rosenbusch had devised a tionally have turned to detergents, which “You have to do an enormous amount way to achieve their goal. They reasoned that remove fats the way soap removes dirt—by of work,”agrees Richard Henderson, a the membranes’ own three-dimensional net- forming protective belts around the pro- structural biologist at the Medical Research work of lipid bilayers would stabilize mem- tein. But detergents also can damage pro- Council in Cambridge, England. A pioneer brane proteins in a way that artificial deter- teins, and milder substitutes that accom- in membrane-protein research, Henderson gent solutions never could. In essence, the plish the same task have been hard to find. toiled for 17 years before publishing, in team asked, why not try to replicate mem- A second difficulty, related to the first, 1975, the very first structure of bacteri- brane proteins’ natural oil-and-water home? is that membrane proteins are difficult to orhodopsin, which is found in the salt-lov- “Lipids and water are in principle crystallize—a necessary step for getting ing bacterium Halobacterium salinarum. immiscible—they don’t mix,”says Landau, “but we can manipulate them into a new material—the lipidic cubic phase—that allows us to work with membrane pro- teins.”By rapidly dissociating these proteins from their native lipid containment, purify- ing them and then very rapidly incorporat- ing restructured versions of them into the new bilayered material, says Landau, “they are much more stable because they are in a native-like environment.”This technique offers a great practical advantage, adds Navarro, because the onerous process of screening detergents has been eliminated. Since Landau’s arrival at utmb, scien- tists from around the world have come to Galveston to learn the new method, and others are sending protein samples to the lab for characterization. “Our method opens up possibilities to work with unsta- ble membrane proteins that researchers haven’t been able to crystallize in the past,” explains Landau. “Structural biology of membrane pro- teins is one of the most important frontiers in biology today,”he says. “It’s about time these proteins got their due.” — STEVEN J. MARCUS & ALANA MIKKELSEN

Segments of this article were adapted with permission from the UTMB Quarterly, Winter 2001.

hhmi bulletin | september 2001 29 NEWS& NOTES Neuroscience of Music t’s a cool spring evening at Allegheny College in Meadville, Pennsylvania. IThe Alexander String Quartet—profes- sional chamber musicians who perform at the college every year—is tuning up on the stage of Ford Memorial Chapel. As the audi- ence files in, a few students scurry around the balcony attaching electrodes to their classmates’ heads and connecting the wires to large computers hauled across campus for the occasion. For tonight, the old stone church is converted into a living laboratory. This combination concert-experiment was part of an interdisciplinary course, “Neuroscience of Music,” offered for the first time during the spring 2001 semester by faculty neuroscientist Jeff Cross and his colleagues—electrophysiologist Alexander Dale and concert pianist Alec Chien. “It is the participant model of science,” Dale says. “The subject participates in the

research.” The pilot course was so success- LEVIN DANIEL ful that the scientists will soon team up Alexander Dale, Jeff Cross and Alec Chien (left to right) blended their scientific and musical expertise with visual artists and dancers to provide to teach students about research. new and unique learning experiences for the students, while further investigating notes, the master musicians are more college encourages cross-disciplinary col- the workings of the human brain. “Neuro- familiar with the music and can anticipate laborations, students were showing interest science has the wonderful advantage of the key changes. Still, “being able to detect in learning about music and the brain and being applicable to every human endeav- this expertise with EEG is truly exciting,” the local Alexander String Quartet—having or,” Dale explains. says the electrophysiologist. participated in an annual artists-in-resi- Supported by a grant from hhmi, the Both science students and music majors dence program on the campus for 10 music course involved a series of concerts say they benefited from the course. Jessica years—was a handy resource. in which electroencephalograms (EEGs) Hoge, a pianist who majored in music and In next spring’s course, using vocal recorded alpha and beta brain waves of stu- neuroscience, used the data generated by music as stimuli, new telemetry equipment dents as they listened to the music. Later, in the concert-experiment for her senior thesis will allow the researchers to leave the heavy the laboratory, the students measured the and submitted a scientific paper for publi- computers in the lab. A new imaging sys- brain activity of the quartet members as cation. She says the whole experience has tem will enable them to map more regions they listened to the piece of music they had influenced her music as well. “When I play of the brain. performed earlier. Comparisons showed now, I’m definitely aware of the mechanism In addition to the music course, other that alpha-wave patterns—characteristic of working in the listeners’ brains.” cross-disciplinary courses will include relaxed wakefulness—were similar in both Chien adds that musicians have long “Neuroscience of the Visual Arts,”“Neuro- sets of listeners. suspected the effects of music on the brain, science of Dance,”“History of Neuro- As expected, Cross says, beta-wave pat- but “now we have proof.”For nonmusi- science” and a philosophy course called terns—those indicating intense mental cians, the hands-on activity was critical to “Mind and Brain.”Dale says he is looking activity—appeared in both groups in the the learning of the science, Cross says. forward to these new collaborations. “The brain’s right frontal area in response to Music brings familiarity and relevance to faculty gets so excited about these models,” changes in key. However, the beta waves the classroom. “It makes our job easier.” he says, “and, when you get the faculty appeared an average of four measures earli- A number of factors inspired Cross, excited, that excitement is absorbed by the er in the quartet members. Of course, Dale Dale and Chien to create the course. The students.” —CAMILLE MOJICA REY

30 hhmi bulletin | september 2001 Mini-Courses in Moscow mini-course on immunology and tumor immunology is routine— A except when it involves two Ameri- can scientists traveling to Moscow to lead the event.“It may be a seditious thing to say, but we actually don’t have serious education in immunology, and particularly in tumor immunology, in Russia,”says course organiz- er Sergei Nedospasov, an hhmi international

research scholar at the Engelhardt Institute of LAMONT DAN Molecular Biology of the Russian Academy of Local students Genevieve Rinker (left) and Rebecca Hopson help Anchorage-based Imaginarium bring Sciences.“The need for such lectures is vital.” the excitement of science to Alaska's children. Philip Greenberg of the University of Washington and Robert Schreiber of the Washington University School of Medicine New Museum Grants Awarded led the four-day course in May at Moscow University’s Center for Molecular Medicine. wenty-nine museums, aquariums, zoos and nature centers have won new hhmi They are among more than 15 researchers, grants totaling $12 million. A number of the programs focus on environmental including several hhmi investigators, who Tstewardship in inner city, rural and other areas where there are high concentrations comprise a “visiting faculty” that has begun of disadvantaged children and families. The Fairchild Tropical Garden in Miami, for exam- traveling to Russia to discuss the latest ple, will receive a $290,000 grant to reach the local, largely Cuban, community. The pro- achievements in immunology in general and gram, called Green Treasures, involves schoolchildren, teachers, families and older people tumor immunology in particular. Nedospasov who emigrated from Cuba in hands-on study of the scientific, economic and cultural launched the three-year educational program importance of plants. The objectives of the grants are to strengthen the science literacy of last September with support from the New teachers, children and their families; to provide resources for improved science teaching; to York-based Cancer Research Institute and the engage families and communities in science education; to develop an interest in science- Ludwig Institute for Cancer Research. education and research careers; and to foster collaboration between informal science edu- Nedospasov wants his colleagues, espe- cation centers and other community institutions. cially younger scientists, to have more contact A list of the new grantees follows. Profiles of some of the programs can be found on with leaders in immunology research. On a the hhmi Web site at: www.hhmi.org/news/071001.html. competitive basis, he helps select groups of 10 Arizona Science Center, Phoenix, Ariz. The Maritime Aquarium, Norfolk, Conn. to 15 trainees from Russia and other coun- tries of the former Soviet Bronx Zoo, New York, N.Y. Missouri Botanical Garden, St. Louis, Mo. Union to participate in Cable Natural History Museum, Cable, Wis. Museum of Science, Boston, Mass. , Md. “journal clubs” with the Chicago Academy of Sciences Peggy Note- National Aquarium in Baltimore lecturers and attend the baert Nature Museum, Chicago, Ill. New Jersey State Aquarium, Camden, N.J. larger lectures. Chicago Botanic Garden, Glencoe, Ill. Rock Creek Nature Center, Washington, D.C. Program organizers , St. Paul, Children’s Discovery Museum, San Jose, Calif. The Science Museum of Minnesota say they hope that if the Minn. The Children’s Museum, Boston, Mass. program proves success- The Seattle Aquarium, Seattle, Wash. ful over its three years, Dakota Science Center, Grand Forks, N.D. Sedgewick County Zoo, Wichita, Kan. colleagues will begin to EcoTarium, Worcester, Mass. Staten Island Children’s Museum, participate in greater Fairchild Tropical Garden, Miami, Fla. Staten Island, N.Y. numbers, leading to UC Berkeley Museum of Paleontology, Garden in the Woods of the New England more such efforts in Berkeley, Calif. Wildflower Society, Framingham, Mass. Moscow and elsewhere. University of California Botanical Garden, , Mobile, Ala. The program’s Web site The Gulf Coast Exploreum Berkeley, Calif. , Anchorage, Alaska Nedospasov is lmi.webzone.ru. The Imaginarium University of Wisconsin–Madison Arboretum WILLIAM K. GEIGER —ANDREI ALLAKHVERDOV Irvine Natural Science Center, Stevenson, Md. Zoo New England, Boston, Mass.

hhmi bulletin | september 2001 31 NEWS& NOTES

Medical student Tamiko Katsumoto explored blood-cell development during HHMI fellowship.

tain hematopoietic stem cells, could not alone help the irradiated mice to recover. However, she could save them by trans- planting bone marrow. Both fetal liver and bone marrow con- tain stem cells that should be capable of restoring bone marrow. Why couldn’t the fetal liver cells alone manage it? Katsumoto began focusing on the potential role of accessory cells, which aren’t stem cells but somehow support the engraftment process. Accessory cells are prevalent in bone mar- row, but exist at much lower concentra- tions in fetal liver. When Katsumoto mixed fetal liver cells with accessory cells derived from bone marrow and injected them into irradiated mice lacking GM-CSF, the bone marrow regenerated and the mice were rescued. “These accessory cells aren’t the immature precursor cells that reconstitute hematopoiesis,”Katsumoto says. “Still, these cells were somehow facilitating engraftment.” However, enough accessory cells had to be present to compensate for the injury to the stroma that occurs in response to irra-

PAUL FETTERS PAUL diation. Will adding GM-CSF protect and nurture sufficient numbers of accessory cells to improve engraftment? Katsumoto Reason to Stay Another Year hopes to find out. “What we can start thinking about o travel the path of discovery, one ma—the spongy mix of fat, fibroblasts, doing,”Katsumoto says, “is using GM-CSF had better be open to extending the macrophages and other components that to improve engraftment. This might be Tadventure a little while longer. support blood-cell development. especially important when umbilical-cord That’s exactly what medical student “I realized around February of that first blood or other sources of stem cells that Tamiko Katsumoto found herself doing year that we had a really striking result,” contain few accessory cells are used.” when her project dropped tantalizing Katsumoto says. “If I wanted to carry the Her project mentor, Kevin Shannon, results in her lap. project through, I needed another year.” noted that his lab, which mainly focuses on Originally scheduled to spend one Katsumoto, who was doing her research leukemia, would not normally have pur- year in the lab of Kevin Shannon at the under an hhmi medical student research sued this line of research. With Katsumoto University of California, San Francisco fellowship, decided to apply for a second preparing to complete her last year of med- (ucsf), Katsumoto ended up adding year of support. She was among the very ical school, however, he says the lab will do another year to her stay in order to few who received it. so, at least for the short term. explore fundamental mechanisms of She was working with mice lacking the When she graduates from ucsf,Kat- hematopoietic stem-cell engraftment—the gene for granulocyte macrophage-colony sumoto is sure she will pursue internal means by which immature blood-forming stimulating factor (GM-CSF)—a substance medicine, although she admits she is also cells take up residence in the fetal liver and that stimulates the growth of certain blood fascinated by hematology/oncology. “I real- then move on to the bone marrow. In the cells. After irradiating the mice lacking ly just love the practice of medicine,”she process, she uncovered a previously GM-CSF to destroy their bone marrow, she says. “It’s so wide open—there are so many unknown role for the bone marrow’s stro- discovered that fetal liver cells, which con- opportunities.” —LISA CHIU

32 hhmi bulletin | september 2001 A River Runs Through Us he Texas town of McAllen shares more than a border with its TMexican neighbor, Reynosa, in the state of Tamaulipas. The Rio Grande/Rio Bravo Watershed is the region’s primary water source, and it is one of North America’s most endan- gered river systems. In May, the McAllen International Museum brought a mobile, hands-on exhibit—Our Water- shed—to the Universidad Autonoma de Tamaulipas. It is part of a bilingual envi- ronmental education project called “A River Runs Through Us,”supported in part by a science education grant Above: Sixth graders from Lower Left: Carlos Alberto Pérez Lower Right: A visiting student from hhmi. Children from six Reynosa Colegio Reforma, a Reynosa Abrego, left, and Rámon David plays the role of "watermaster," area high schools were trained by muse- elementary school, use a model of Pérez Hernandez, students at whose task is to distribute um staff to serve as guides to the 4,200 the Rio Grande/Rio Bravo Water- CETIS 71, a Reynosa high school, fairly—among cities, industry, elementary school students from 30 shed to see how dams change the operate small hand pumps to agriculture and wildlife—the flow of a river. cause “rain” to fall from clouds in water that McAllen and schools who visited the exhibit. a model of the water cycle. Reynosa share. ANSEN SEALE ANSEN (3) SEALE

hhmi bulletin | september 2001 33 NewNotes.Final 10/9/01 8:19 PM Page 34

N E W S & N O T E S

th r ee basic que s ti on s . How long does it take If You Can Name Tha t Ton e , you to tell what a tone is? The y res p ond , “Im m ed i a t ely.”How long have you known you have perfect pitch? “M y whole life. ” Thank Your Pare n t s — How accu ra t e are you? “I never miss.”

and Your Music Tea c h e r Is this a case of na t u r e needs nu rt u re ? JG: Exa ctl y. You need to have some kind of A conver sation with Jane Gitsch i e r training to develo p perfect pitch. It makes sen s e . You cle a r ly need to be expo s e d to the ane Gitschi e r, hh m i in ves ti ga t or at How rar e is perfect pitch, reall y ? defi n i ti o n of a note—this is a D-flat, this is the Uni versi t y of Cal i f orni a , San Jane Gitschier: I gave a talk on perfect pitch an A-s h a r p. If you don’t get that mus i c a l JFran c i s c o (uc s f ) ,s tudies the gene tic at hh m i last yea r . The staff ha d the Stein - in p u t by a certain age ,a round age six, you’ l l basis of chi l d h o od disorders. One of he r lat- wa y tun e d for the occa s i on . I gave the audi- lose the cha n c e to have perfect pitch even if est exp l o ra ti on s ,i n s p i red by her training as enc e of abo u t 100 people our operat ing defi - you have the rig ht all el e . a classical singer, is the gene tics of perfect ni ti o n of perfect pitch: If I played a tone pi t ch—less a disorder than a rar e mus i c a l wit h o u t an ext ernal reference , a perso n wit h Can a perso n develo p perfect pitch wit h - gif t . With col leagues at uc s f , in c lud i n g perfect pitch could ident ify that tone . The n I ou t the gene tic predi s po s i ti o n? Nels o n Freim e r, no w at the Uni versi t y of pl a yed four notes on the piano. Just one per- JG: People claim you can, but I’m dubi o u s Cal i f orni a , Los Ang el e s ,G i t s ch i er has fou n d son , a pos t doc, qui ck l y rai s e d his hand and abo u t it. You can develo p very good rela t ive that this abil i t y to name a note ,i m m ed i a tely correctl y named the four notes . The audi- pi t ch— g et to know what an A feels like on and eff ortl e s s l y, whe n it is sounded tends to enc e appl a u d ed. It’s very clear that this is an a vio l i n , for exa m p l e . You might seem to run in families. The res e a r che rs don’t yet abi l i t y the averag e perso n does not have. ha ve perfect pitch. But you may not have it kn o w whi c h gene or genes are res p ons i bl e , on other instrum en t s . but they’ ve begun the linkage studies to find Do people with perfect pitch know they out . The y do know, ho wever, that the trai t ha ve it? How wil l this res ea r ch bene fit people in requi r es early musical training to blo om. JG: Yes , and they give the same answers to mus i c ? JG: (Lau gh i n g ) I don’t think th e re is an y appl i c a ti o n for people in mus i c . I think there’s a lot of app l i c a ti o n for sci- enc e—in the stud y of brai n develo pme nt and neur ona l pl a s ti c i t y, and in educ a ti on a l is s ues as well. For ex a m p l e ,i t could help us deci d e whet h e r to exp ose our chi l d r en to cer- tain things ,l i ke new languages . I trie d to give my daught er piano lessons by the time she was six yea r s old. It beca m e obvious to me that she does not have perfect pitch, so I did- n’t push it. On the other hand, sh e ’s doing a bea u tiful job le a r ning Chi n e s e . —CORI VA N C H I E R I

Think you’ v e got that magical ab i l i t y to name that tune in one no te? Tes t your inborn skill with Gi t s c h i e r ’ s pitch tes t online at: www.h h m i .o rg / b u l l et i n . Jane Gitschier exp l o r es the genetics of perfec t pitch. She and daughter Annie Stei n b e r g enjoy playing music tog et h e r .

34 h h m i b u ll e t i n | s e p t e m b e r 2 0 0 1 A Science Connection in Roxbury ocated in the heart of Roxbury, a largely minority, inner-city neighbor- Lhood of Boston, the James P. Timilty Middle School shines in science education. In the rigorous statewide achievement tests for the eighth grade, Timilty’s students outscored most of Boston’s schools in sci- ence and technology and in a combined measure of achievement in four broad sub- ject areas. The school has been singled out with several national and statewide awards for its overall high student performance.

Timilty’s success, administrators say, ROWIN STANLEY reflects several factors, including its skilled Eighth grader Javier Martinez-Gonzalez demonstrates his award-winning research project with a fel- and dedicated staff; its adoption of Project low student. He compared the lung capacity of boys and girls through a calibrated arrangement of Promise—a program featuring an extended buckets and a tube immersed in water. school day, team teaching, shared decision making and smaller classes; its inspired stu- sional classroom lecturers and hosts to to “demystify” science for the students. Sci- dents and a little help from its friends. young visitors. Since 1994, the mgh/Tim- ence Connection’s longest-running activity Since 1989, a partnership with nearby ilty Partnership has been strengthened with in this spirit—its “cornerstone,”says Massachusetts General Hospital (mgh) has the Science Connection program, funded Prince—is the Science Fair Mentoring Pro- enabled the school to tap the hospital’s by an hhmi grant. gram. Each mgh volunteer is paired with a resources. Each year, some 250 hospital The objective, says the partnership’s Timilty student for the six months leading employees spend time as mentors, occa- administrative director Carlyene Prince, is up to the school’s annual science fair. Stu- dents are chosen not so much for their grades as for their motivation, says Timilty science teacher Robert Cho, the program’s NEW UNDERGRADUATE COMPETITION former manager. They are “kids who really HHMI has invited 200 research and doctoral universities to apply for a new round of under- wanted to be in the program.” graduate biological sciences education grants. An estimated 50 to 60 four-year grants rang- In 2001, Timilty sent more student ing from $1.2 million to $2.2 million will be awarded in 2002. projects to the citywide science fair than In addition to the existing objectives, such as preparing students for careers in biomedicine any of Boston’s 26 other middle schools, and providing engaging science curricula for nonscientists, new program objectives include: and many won awards. The Science Con- nection program has additional compo- Enable graduate students and postdoctoral fellows to supplement their research training nents. “Science in the Classroom” features with teaching and mentoring experiences that prepare them for roles as scientist-educators. teaching stints by mgh employees ranging Develop models for overcoming the traditional dichotomy between research and teaching. from one-time visits to continuing rela- Foster a team approach to research among faculty, undergraduates, fellows and graduate tionships with a class. Twice a year, the stu- students. dents’ family members join in for “Science Explore the interactions of biology and other disciplines, including mathematics and com- Family Activity Night.”“We expose these puter science. young men and women, who often live in a very small circle, to science,”says mentor Share university educational resources with other institutions, including colleges and sec- Guillermo Banchiere, director of environ- ondary and elementary schools. mental services at mgh. “By showing them Provide increasingly challenging science experiences to undergraduates during their four- lots of things they probably didn’t know year college stay. —JENNIFER BOETH DONOVAN existed, we expand the universe for them.” —STEVEN J. MARCUS

hhmi bulletin | september 2001 35 HHMI LAB BOOK RESEARCH NEWS FROM HHMI SCIENTISTS

IN BRIEF fellow at Washington University in St. Louis, Room for published their findings in the May 11, 2001, Fault the ion channel Genetic mutations issue of Science. that yield flaws in a specific ion channel have Improvement “This finding is important because it been tied to a rare disorder characterized by shows that the statins work by attaching muscle paralysis, irregular heartbeat and themselves to an inactive form of growth problems. The finding offers a new per- in Statin Drugs HMGR,” says Deisenhofer. “That suggests spective on how faulty ion channels—pore-like that you can’t assume that a drug will proteins that poke through cell membranes and esearchers have provided the first have its effect by attacking the active form control the flow of potassium, sodium and other molecular look at how a popular of an enzyme. You may have to design a ions into and out of the cells—can cause disease Rfamily of cholesterol-lowering drugs drug that attacks the inactive form of the in humans. Researcher: Louis J. Ptáˇcek. does its work. They’ve captured images of enzyme and prevents the enzyme from www.hhmi.org/news/ptacek3.html the widely prescribed statin drugs, includ- becoming active.” ing Lipitor and Zocor, in the process of The researchers also noticed that exist- Motor neurons need vitamins Spinal blocking cholesterol synthesis—and they ing statins fail to block an additional region muscular atrophy (SMA), the most common see room for improvement. of HMGR, suggesting that the drugs might genetic cause of infant mortality, may be exac- Statins block the enzyme HMG-CoA be improved to more tightly bind to the erbated by insufficient amounts of folic acid and reductase (HMGR) from grabbing hold of enzyme and further reduce its activity. vitamin B12 in the diet. The HHMI investigators a molecule called HMG-CoA to begin cho- Deisenhofer emphasizes, however, that who made this discovery plan to collaborate lesterol production. As a result, the cell suf- tight binding to the enzyme may not be the with clinical scientists to explore whether vita- fers a shortage of cholesterol and compen- whole story. Statins appear also to interact min therapy might offer some relief from the sates by importing ready-made cholesterol with other proteins, as evidenced by their muscle weakness and wasting experienced by from the bloodstream. This, in turn, lowers effects on blood-vessel growth, bone for- SMA patients. Researcher: Gideon Dreyfuss. cholesterol levels in the blood. mation and the immune system. www.hhmi.org/news/dreyfuss2.html The scientists used x-ray crystallography www.hhmi.org/news/deisenhofer.html to produce images of six different statins —MARC KUSINITZ Genes and benign tumors Researchers binding with HMGR. Although the have determined the normal role of two genes statins have different shapes, they that are mutated in the inherited disorder all imitate part of the HMG-CoA tuberous sclerosis complex. Ordinarily, these molecule, and trick HMGR into genes, Tsc1 and Tsc2, help regulate cell growth grabbing hold of the statin. This and organ size; their protein products are likely coupling twists the enzyme slightly part of the insulin-signaling pathway. These out of shape, preventing it from genes may offer a novel target for treatment of forming its active site—the busi- type 2 diabetes, as well as tuberous sclerosis ness end of the enzyme that binds complex, which causes widespread benign with HMG-CoA. hhmi investiga- tumors in the brain, skin, lungs and kidneys. tor Johann Deisenhofer at the Uni- Researcher: Tian Xu. versity of Texas Southwestern Med- www.hhmi.org/news/xu2.html ical Center in Dallas and Eva S. Istvan, now an hhmi postdoctoral Tracking forward motion Researchers S. ISTVAN JOHANN DEISENHOFER AND EVA have distinguished some of the cues that the A representation of part of the surface human visual system uses to estimate the of HMG-CoA reductase (yellow and speed of an approaching object. As the object green) shows how one statin drug, sim- gets closer, the visual system extracts informa- vastatin (purple), binds to the enzyme. tion about its motion by estimating the rate of The drug blocks the enzyme from change in its size. becoming active and instigating Researcher: Eero P. Simoncelli. cholesterol synthesis. www.hhmi.org/news/simoncelli.html

36 hhmi bulletin | september 2001 IN BRIEF

Brain wiring turnabout A potent chemical signal known to guide the wiring of neurons in the developing nervous system also steers migrating muscle fibers to their proper connec- tions. The signal initially repels muscle cells, and later becomes a powerful attractant. The dis- covery of the signal’s dual role, and its drastic turnabout, shows how tissues may use the same signals for different purposes during development. Researcher: Corey S. Goodman. www.hhmi.org/news/goodman2.html

Where cell death begins Two proteins inside the cell, BAK and BAX, are essential to setting off programmed cell death (apoptosis). They act by disrupting mitochondria, the cell’s

WAYNE M. YOKOYAMA, ADAPTED BY TRAVIS DAUB TRAVIS BY ADAPTED M. YOKOYAMA, WAYNE energy-producing machinery, causing leakage of Yokoyama and colleagues propose that natural the protein cytochrome c and triggering cell killer (NK) cells express a receptor, Ly-49H, that death. Inhibiting BAK and BAX activity may First-Line enables them to recognize a ligand (purple trian- ease nerve-damaging disorders that involve gle) on the surface of cells infected with murine excessive apoptosis, whereas promoting the Virus Fighters cytomegalovirus. This leads to activation of the proteins’ activity might slow the runaway cell NK cell to release granules (orange balls) that growth of cancer. Researcher: Stanley J. esearchers have discovered a sensing disrupt the infected cell's plasma membrane and Korsmeyer. molecule on the surface of natural cause the cell to die. www.hhmi.org/news/korsmeyer.html Rkiller (NK) cells that enables them to battle viral infections. The finding is an studied the immune response of the BXD-8 How the brain’s clock ticks By creating important step in understanding innate strain of mouse, which lacks only the Ly- mice with a mix of cells that produce either immunity—how the body rapidly launches 49H receptor on NK cell surfaces. Without normal or abnormal circadian rhythms, its first strike against invading pathogens this receptor, the mice were susceptible to researchers are learning how neurons synchro- before other components of the immune murine cytomegalovirus. In addition, when nize their behavior to control the body’s 24-hour system can take action. Ly-49H was inactivated in mice that pos- internal clock. Researcher: Joseph S. Takahashi. NK cells are lymphocytes best known sessed the receptor, the mice died, unable to www.hhmi.org/news/takahashi3.html for their ability to kill developing tumor control the virus. These studies provided cells. They have also been thought to count- key evidence that the Ly-49H receptor Virus wraps up ribosome Researchers have er infections in the earliest phases of the sparks the NK cells’ attack against the virus. discovered how hepatitis C virus (HCV) forces body’s immune response, but how these “These findings strongly suggest that infected cells to shut down their own protein syn- cells could attack their targets had never NK cells have a specific role in immunity thesis and make the virus’ proteins instead. Addi- been demonstrated, according to hhmi that was not previously known,”says tional studies might reveal ways to block this investigator Wayne M. Yokoyama and col- Yokoyama. “NK cells apparently use Ly-49H HCV takeover strategy, thereby improving treat- leagues at Washington University School of to recognize something on the membranes ments for HCV infection. Researchers: Jennifer Medicine in St. Louis and coauthor Anthony of cells infected with murine cytomegalo- A. Doudna and Joachim Frank. A. Scalzo at the University of Western Aus- virus and initiate an immune response that www.hhmi.org/news/doudna.html tralia. Their findings were published in the destroys those cells. This further implies May 4, 2001, issue of Science. that NK cells may use this receptor or oth- Fly genes for taste and smell By identify- By exploring the region on mouse ers to recognize and attack other infec- ing a large family of fruit fly genes involved in chromosome 6 known to contain clusters tions.”Basic understanding of NK cell acti- taste and smell, scientists have taken a signifi- of genes for receptors found on NK cells, vation could lead to better treatments, cant step toward deciphering the molecular they found a receptor called Ly-49H that especially for people with aids and others logic of odor and taste perception. This work accounts for the ability of some mice to with weakened immune systems who are could lead to improved methods for protecting resist otherwise lethal infection with highly susceptible to viral infections. humans and crop plants from insects. murine cytomegalovirus (a herpesvirus www.hhmi.org/news/yokoyama.html Researcher: Richard Axel. that infects mice). The researchers then —MARC KUSINITZ www.hhmi.org/news/axel2.html

hhmi bulletin | september 2001 37 HANDS ON May I Take Your Mouse Order, Please?

t’s not quite as routine as other institutions supplied the ordering a magazine or a strains to the laboratory for Ibouquet of flowers, but the breeding and distribution to process of buying specialized the scientific community. mice for experiments in genet- The lab distributes mouse ics and related fields has dna as well as live mice, and it become commonplace. The is assessing the feasibility Jackson Laboratory, which runs of shipping frozen mouse the world’s largest mouse embryos or sperm that repository, supplies approxi- researchers could use to build mately 2 million mice each year their own mouse colonies. All to universities, medical schools materials undergo rigorous and research laboratories. quality-control testing to The not-for-profit institu- ensure health and genetic tion in Bar Harbor, Maine, also has its own purity. The lab also maintains a comprehen- research program, whose investigations range sive database about mouse genetics, which is from diabetes to sleep disorders, and it offers available through its Web site, www.jax.org. a variety of training programs for visiting sci- hhmi has provided more than $5 million to entists. It remains best known, however, as help the Jackson Laboratory meet the grow- the place that researchers call to get mice bred ing demand by researchers for genetically with a vast array of genetic variations—more altered mice. H than 2,500 strains. Already the most widely studied research model for human diseases and disorders, the mouse has become even more essential since scientists developed techniques to “knock out” or otherwise mod- ify specific mouse genes, most of which have close human counterparts. Researchers interested in genes connected with cancer, for instance, can find hundreds of mouse strains that might be useful. Stock Scientists from around the number 002265 is a mouse that lacks the Bcl2 world can order mice by phone, fax gene involved in leukemia and other cancers, a or mail, or online at jaxmice.jax.org. characteristic that makes it useful in the study They can use credit cards and of cancer itself or in learning about underlying other forms of payment but encounter some interesting biological processes such as programmed cell restrictions. Some mutant mice, death. Other mouse strains related to cancer for instance, must travel with are so numerous that the lab’s 535-page cata- hardier mice, called shipping log lists them under “Oncogenes,” “Growth companions, to survive the stress Factors” and similar categories. The catalog of shipment. Scientists also need to provide advance notice if they also offers mouse models for numerous other want pregnant females, which do disorders. Scientists at the Jackson Lab, like best if shipped between the 11th Simon John, an hhmi investigator who stud- and 15th days of pregnancy. ies the genetics of glaucoma, and at numerous

38 hhmi bulletin | september 2001 The older the mouse, the more it costs. This mouse costs $157.70 at three to five weeks of age and $162.65 at eight weeks. A breeding pair costs $195.20. The prices for other strains vary. There are also shipping fees—$9.00 per container—and charges for items such as export documents.

Inventory control is a challenge for the lab, which provides colonies to match demand whenever possi- ble but sometimes must restrict quantities of certain strains. Many factors affect the availability of a strain, especially when it is first released for distribution. These include how well the strain breeds, the size and viability of typical litters and whether one gender is preferred as a research model. For example, both of these mouse Some mice, like the first one strains are useful in cancer described here, have genetic muta- research. Scientists can order only tions that occurred spontaneously as many as 10 of each sex per in nature. Others, like the second month of the first strain, but they entry, have mutations that can order 25 or more per month of researchers created deliberately. each sex of the second strain.

hhmi bulletin | september 2001 39 CLOSE- UP dendrite. This means that an activated synapse need not send a signal to the cell body to make new protein and ship it back. “Home-Grown” Proteins There is a local control mechanism. The events at the synapse are in very close proxim- ity to the protein-synthesis machinery.” Build Synaptic Strength In practical terms, Schuman notes that the protein involved in fragile X syndrome, a genetic abnormality that causes mental any neuroscientists believe that when and where they’re needed, rather than retardation, is an RNA-binding protein synaptic strength—the ease with import the proteins from the cell body. found in dendrites. “Understanding dendrit- Mwhich a signal traverses the Proving this hypothesis required consid- ic protein synthesis may help us understand, synapse, which is the gap between two erable experimental dexterity. Schuman’s somewhere down the line, what goes wrong neurons—plays a central role in learning studies used green fluorescent protein (GFP), with fragile X syndrome,”Schuman says. If and memory. When a music student first derived from jellyfish, to signal that protein that hope is not realized, there is still a reads “C major 7 chord” on a score, for synthesis was occurring. Her team built a broader benefit: Every step toward example, it takes considerable effort to “reporter” molecule containing the GFP understanding the transmission of nerve sig- strike the correct keys on the piano. After messenger RNA (mRNA), which carries the nals across synapses produces a clearer reading and playing the chord 500 times, DNA’s instructions for synthesizing proteins picture of learning and memory. however, the neural pathway that in the ribosomes. The team flanked the GFP — DAVID TENENBAUM translates a visual image into a musical with two key elements: one that causes the concept and then into a fingering pattern reporter mRNA to travel from the cell body becomes established, enabling the fingers (where it is made) to the dendrite, and hese images show protein synthesis occur- to strike the keys faster and more accurate- another that responds to the neuron’s signal T ring at the dendrite, where proteins are ly. At the molecular level, the “wearing in” to “make protein” by regulating the synthesis ultimately needed to build synaptic strength. of this neural pathway translates into the of GFP on the mRNA template. They reveal an efficient system for learning and building-up of synaptic strength and a To start the protein synthesis, Schuman memory. Instead of proteins being produced in more powerful signal. used a growth factor called BDNF. After a the neuron cell body and shipped to the far- The cell biology of this process has few minutes, reporter protein levels in many flung dendrites, they are synthesized locally, posed a paradox, however. To build synaptic parts of the dendrites did rise, as shown by right where they do their work. strength, new proteins are needed the increased brightness of GFP under a immediately at the dendrites, the synapse- light microscope. forming branches emerging from the body To prove that the proteins were being of the neuron. These proteins must be trans- synthesized in the dendrites, Schuman and ported from elsewhere because, according to her graduate students Bryan Smith and conventional wisdom, they are made in ribo- Girish Aakalu tried several hundred times to somes inside the cell body, not in the keep dendrites alive after being severed from dendrites. If so, how are the proteins the cell body. The neurons came from the rat transported to the correct synapse quickly hippocampus—a part of the brain that is enough to account for learning? essential for learning and memory. Roughly Erin M. Schuman, an hhmi a dozen dendrites survived, and each showed investigator at the California Institute of protein synthesis after stimulation with Protein Technology, has investigated this apparent BDNF, indicating that the synthesis must synthesis Highest anomaly and now offers another view. have occurred in the dendrite rather than the SCIENCE. © 4 ELSELVIER FIGS. & 30: 9 1-20 (2001) “Since we know that all synapses are cell body. individual, protein would have to be The data were intriguing. For one thing, NEURON shipped to each, and that would be a traffic throughout the experiment, protein synthesis nightmare,” she says. Instead, Schuman con- occurred at the same spots within the cludes that dendrites use a “home-grown- dendrite, suggesting that locally synthesized protein” approach that is considerably proteins might be delivered to only a few swifter and surer than the problematic synapses. These experiments, Schuman stress- “manufacture-and-ship” tactic. Using a es, show the simplicity of a process that’s technique that she invented, she has shown essential to learning and memory. “Our data Lowest that dendrites make the proteins themselves, show that protein is made right in the FROM REPRINTED WITH PERMISSION

40 hhmi bulletin | september 2001 ERIN M. SCHUMAN Protein synthesis along dendrites, seen at On a single, severed dendrite, protein Ahigh magnification. Upper: part of a den- B synthesis lasts hours after the BDNF drite before stimulation with BDNF. Lower: stimulus. The five colored trails indicate pro- same dendrite after stimulation. The location tein synthesis at 30-minute intervals after of synthesis does not change, but it intensifies stimulation. Distance from the cell body (bot- Dendrites before (left) and 120 minutes after stimulation, as shown by the transition tom scale) shows synthesis taking place in the Mafter (right) BDNF treatment. Arrow from blue to red and the appearance of blue in same locations—possibly at synapses. shows where the dendrite was severed from the dendritic spines. the cell body.

hhmi bulletin | september 2001 41 FROM THE TOOLBOX

two components: the first, a gene that produces a blue color in cells carrying it; and Trapping the Genes the second, a drug-resistance gene. Thus, the embryonic stem cells with insertions in genes (rather than insertions in the non-gene that Wire the Brain components of the cell’s dna) could be isolated by applying a drug to weed out those n a molecular choreography of great time,”says Tessier-Lavigne. It took him and cells that did not take up the drug-resistance precision and timing, young neurons his colleagues more than four years, for gene. The desired cells could also be Iare alternately attracted and repelled by example, to identify the netrins, a small fam- distinguished by their blue color. different molecules as they wend their way ily of axon-guidance molecules. With the In 1995, Skarnes refined the gene-trap toward targets in the brain and spinal cord. team’s new “gene-trapping” technique, technology by including a gene segment that Disruption of this delicate process and the however, researchers can cast a much wider would activate the blue marker only if the consequent misrouting of neurons can have net to study many genes simultaneously and dna had fused itself into a gene for a secret- catastrophic consequences—schizophrenia then determine the effects of mutations in ed protein or membrane protein, such as a and autism, for example. those genes. receptor. This refinement, called a secretory Despite the daunting nature of the task, The improved gene-trapping technique trap, enabled the researchers to narrow the researchers are making remarkable progress described in Nature was built on two genera- list of trapped genes to those coding for in understanding how trillions of neural tions of gene-trap technology. In the original signals or receptors involved in axon circuits are formed in the mammalian brain, method developed in the 1980s, genes in guidance. especially how different types of molecules mouse embryonic stem cells were mutated “The secretory trap is a nice bonus,”says alter the trajectory of axons. Located at the by randomly inserting a genetic marker with Tessier-Lavigne,“because we can focus on tip of neurons, axons contain all of the exactly the kinds of molecules “hardware” needed to pilot growing neurons we’re interested in—mainly through the nervous system. Axons are receptors and ligands (the stippled with receptors that enable them to molecules that bind to receptors). sense and respond to molecular guidance These genes represent a small frac- cues. If a receptor binds to an attractant mol- tion of the genome, and this trap ecule, for example, the axon is pulled toward concentrates on just that fraction.” a target. Alternately, if the receptor binds to a Even with Skarnes’s improve- repellent molecule, the axon is pushed away. ments, the gene trap needed Understanding how neurons are pushed additional modifications before it and pulled toward their final destinations is was ready to fish out axon- time-consuming work. In addition to being guidance molecules.“In early stud- tedious, the assays and experiments used to ies, we found that mice with discover axon guidance factors in mammals ‘trapped’ neuronal genes didn’t are costly. show proper axon staining because In an effort to speed things up and the blue marker got trapped in the reduce expenses, a team of researchers has neuron’s cell body,”Tessier- developed a faster screening method to iden- Lavigne says. This poor staining tify genes that guide neural wiring in the made it more difficult to explore mammalian brain. hhmi investigator Marc the effects that specific gene muta- Tessier-Lavigne at the University of tions had on brain wiring. California, San Francisco, William C. Skarnes In the work published in at the University of California, Berkeley, and Nature, Tessier-Lavigne and his their colleagues unveiled their new technique colleagues fixed the staining and discussed some of its early applications problem by inserting an additional in an article published in the March 8, 2001, marker, plap (placental alkaline issue of the journal Nature. RIES BARBARA phosphatase), in the gene-trap sys- Marc Tessier-Lavigne says the improved gene-trapping tech- “Until now, we’ve gone about trying to tem. If plap is present, axons are nique enables researchers to zero in on genes that direct grow- identify brain-wiring mechanisms one stained purple.“This modified ing neurons toward their destinations in the brain. guidance event at a time, one molecule at a gene-trap strategy enabled us to

42 hhmi bulletin | september 2001 mutate a gene for a guidance-molecule receptor, and by including the plap marker, we were able to see the purple-stained, altered neuronal wiring and rapidly assess what had gone wrong with the wiring process,”says Tessier-Lavigne. Using the modified technique, the researchers produced 46 lines of mice with defined defects in axon-guidance molecules. “With these mice, we have proven that we can trap genes that are specifically expressed in the nervous system,”he says.“We can also see discrete patterns of axonal labeling, and we can uncover mutant phenotypes.” Studies on two of the genes—Sema6A and EphA4, known to be involved in neural development—demonstrated that the trapping method could also identify axon- guidance mutants.“With EphA4, we showed that we could reconstruct a known mutant and use it to learn additional information about where the gene is expressed and how the mutation alters brain wiring,”says Tessier-Lavigne.“And with Sema6A,we showed that we could use the technique to discover a new mutant that affects only a small subset of axons in an otherwise normal nervous system.” These results suggest that the new gene- trapping method may enable rapid progress in understanding how neurons wire the brain.“Neurons that project their axons to a particular area follow a code of transcription-factor activation that presumably activates genes for surface recep- Above: In the brain of a neonatal mouse, gene-trapping without PLAP staining (top) shows a blue color at tors that, in turn, dictate what the axon the position of cells in the cortex, but doesn’t show their axons. With the refined technique using PLAP does,”says Tessier-Lavigne.“We’re hoping NATURE staining (bottom), the axons show clearly in purple. Below: Well-labeled axons cross at the midline of the that gene trapping can help identify an mouse brainstem, then project down the spinal cord to control motor activity. When both copies of the underlying receptor code by focusing very EphA4 gene are disrupted, the axons are misrouted, resulting in clumsy rear leg movements. specifically on receptors involved in axon guidance and finding their expression patterns as well as their mutant phenotypes.” To make these advances widely available to researchers studying the normal wiring pattern of the brain, Tessier-Lavigne and his colleagues are putting their gene-trap data on the Web at www.genetrap.org. The mutant mouse lines produced by this technique should also be of use to fellow researchers. “These mouse lines have very specific populations of axons that are labeled purple,”Tessier-Lavigne says.“In some cases it’s the first time that a marker has been identified for those axons, and those markers

KEVIN MITCHELL,TESSIER-LAVIGNE LAB. REPRINTED WITH PERMISSION FROM KEVIN MITCHELL,TESSIER-LAVIGNE 410 , FIGS. 2A © (2001) & MACMILLAN PUBLISHERS 5C, LTD. 174–179 provide a valuable resource.” H

hhmi bulletin | september 2001 43 HHMI ONLINE Rheumatoid arthritis features a diverse cast of molecular actors. The drama begins when an “antigen-presenting cell,” shown as APC at 1 the top of this stylized drawing, comes in contact with the immune How to ZAP the system T cell, shown in purple. APC displays a distinctive antigen, shown as a green dot, which triggers a cascade of signals within the T cell.

A The antigen binds to the surface of the T-cell receptor, Signals that Lead to 2 shown in pink. B Activated Lck kinase, shown as a glowing red ball, modifies the ITAM subunit of the T-cell receptor. It does so by adding a phosphate group through Rheumatoid Arthritis phosphorylation, a key process that occurs throughout the signaling cascade. C The enzyme ZAP-70 docks onto the region of ITAM that has been or decades, physicians tended to treat rheumatoid arthritis conserv- phosphorylated, shown in white. atively, progressing carefully to the most powerful therapies. During D Lck kinase phosphorylates ZAP-70, shown by a small white circle. the past several years, however, several new drugs have emerged that F E Now activated, as shown by the glowing red, ZAP-70 phosphorylates LAT, permit physicians to treat patients quickly and aggressively to help avoid the white circle within the orange bar. crippling illness. They are using these new drugs, singly and in combina- F The phosphorylated LAT has its turn, providing a docking site for activated tion, to greatly ease the pain, swelling and stiffness that once seemed PLCγ, the glowing red oval. inescapable in a disease that affects more than 2 million Americans. G PLCγ interacts with PIP2, the yellow oval within the T-cell membrane. Andrew C. Chan, a rheumatologist who recently completed eight γ years as an hhmi investigator at Washington University School of H PLC catalyzes PIP2 to produce IP3, the green circles that begin entering the cytoplasm, shifting the action to other parts of the T cell. Many steps remain. Medicine in St. Louis, has treated many arthritis patients and thinks

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these advances are only the beginning. Chan and other researchers have determined in remarkable detail how a complex cascade of 3 molecular events enables the immune system to recognize and attack foreign invaders. In rheumatoid arthritis and other autoimmune dis- eases, such as multiple sclerosis and lupus, the immune system mistak- enly launches an attack against the body it is supposed to protect. By learning precisely how the process works, with one molecular event triggering the next, Chan hopes to find ways of shutting it down in these autoimmune disorders. These illustrations—part of a new animation at hhmi’s BioInterac- tive.org—show some of what Chan and others have discovered about this signaling cascade, which starts with a T cell recognizing what seems to be a foreign antigen and ends with the T cell replicating in huge num- bers. At each step along the way, there’s a flurry of activity. In the begin- ning, for example, enzymes in the T cell’s cytoplasm move to docking sites near the cell’s membrane, where they start interacting in a precise pattern. Chan and his colleagues have shown that one enzyme, ZAP-70, plays an especially important role in this process. Blocking the action of ZAP-70 with new drugs, they hope, may prevent the proliferation of T cells that causes the joint inflammation and other debilitating effects of rheumatoid arthritis. H

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The green circles, or IP3, shown in the last drawing of the previous sequence have now made their way to the T cell’s 3 endoplasmic reticulum, which they signal to begin releasing calci- um. Along with calmodulin and calcineurin, the calcium triggers a transcrip- tion factor, NF-AT, to enter the cell’s nucleus. NF-AT and other transcription factors induce a gene within the nucleus to produce the protein IL-2, which then leaves the T cell.

Multiple copies of the IL-2 protein, shown as blue ovals, bind to receptors on the T cell’s surface, causing the cell to start replicat- 4 ing.

With the IL-2 proteins binding to its surface, the T cell begins reproducing in large numbers. The process is usually beneficial, 5 enabling the immune system to build up its forces to fight dead- ly invaders. In the case of rheumatoid arthritis, however, the proliferating T cells harm the body itself—which is why Chan and others seek to block the signaling process.

A new animation at hhmi’s BioInteractive.org shows in detail the normal T-cell signaling cascade that is activated inappropriately in autoimmune diseases such as rheumatoid arthritis. The Web site also features “virtual laboratories,” click-and-learn demonstrations, scientific lectures and other online learning tools.

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hhmi bulletin | september 2001 45 Protein synthesis Highest

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These images by Erin Schuman and colleagues show proteins being synthesized at dendrites separated from the cell body (at black squares). They indicate that neurons can produce proteins right where NONPROFIT ORG. they’re needed for learning and memory, instead of ferrying them from US POSTAGE the cell body to distant dendrites. The lower image shows increased protein production after addition of a growth factor. Story on page 40. PAID SUBURBAN MD PERMIT NO. 6561 Howard Hughes Medical Institute 4000 Jones Bridge Road Chevy Chase, Maryland 20815-6789 301.215.8855 www.hhmi.org