<<

PRESIDENT OF Michael Levitt Iva S. Greenwald Peter Palese THE ACADEMY Gregory A. Petsko Jeffrey C. Hall Thomas E. Shenk Ralph J. Cicerone Philip C. Hanawalt Thomas J. Silhavy Cellular and Developmental Rudolf Jaenisch Thomas E. Wellems Biology EDITOR-IN-CHIEF Mary-Claire King C. David Allis Physics Jasper Rine Donald D. Brown Anthony Leggett Reed B. Wickner ASSOCIATE EDITORS Eric H. Davidson Paul C. Martin David Chandler Brigid L. M. Hogan Geology José N. Onuchic Alan Fersht Eric N. Olson W. G. Ernst Jack Halpern James P. Kennett and Dolores R. Piperno Pharmacology David D. Sabatini Geophysics Solomon H. Snyder Richard W. Aldrich Gertrud M. Schüpbach Mark H. Thiemens B. L. Turner II Susan G. Amara Peter K. Vogt Cellular and Molecular Human Environmental David Julius Susan R. Wessler Sciences Arthur Karlin Pietro V. De Camilli Ruth S. DeFries Ramón Latorre SPECIAL FEATURE EDITORS Richard L. Huganir Susan Hanson Robert Nerem L. L. Iversen Plant Biology Immunology Stephen F. Badylak Yuh Nung Jan David Baulcombe Peter Cresswell Robert Langer Anthony R. Cashmore Douglas T. Fearon Jeremy Nathans Maarten J. Chrispeels Tak Wah Mak EDITORIAL BOARD Charles F. Stevens Enrico Coen Philippa Marrack Thomas C. Südhof Joseph R. Ecker Animal, Nutritional, and William E. Paul Joseph S. Takahashi Robert Haselkorn Applied Microbial Sciences Ralph M. Steinman Richard W. Tsien June B. Nasrallah David L. Denlinger Tadatsugu Taniguchi R. Michael Roberts Plant, Soil, and Chemistry Arthur Weiss Linda J. Saif Microbial Sciences Stephen J. Benkovic Ryuzo Yanagimachi Mathematics Roger N. Beachy Harry B. Gray Richard V. Kadison James C. Carrington Anthropology Michael L. Klein Robion C. Kirby Brian J. Staskawicz Richard G. Klein Raphael D. Levine Medical Genetics, James F. O’Connell Jerrold Meinwald Psychological and Cognitive Hematology, and Alan Walker Nicholas J. Turro Sciences Oncology Dale Purves Applied Mathematical Sciences Computer and C. Thomas Caskey Edward E. Smith Peter J. Bickel Information Sciences Joseph L. Goldstein David L. Donoho William H. Press Mark T. Groudine Social and Political Sciences Tony Hunter Alejandro Portes Applied Physical Sciences Economic Sciences Philip W. Majerus Brian Skyrms Noel A. Clark Roy Radner Inder M. Verma Francisco de la Cruz Jose A. Scheinkman Sustainability Science Harry L. Swinney Medical Physiology Barry R. Bloom Engineering Sciences and Metabolism William C. Clark Astronomy Evelyn L. Hu Charles A. Dinarello Partha Sarathi Dasgupta Neta A. Bahcall Katepalli R. Sreenivasan Robert J. Lefkowitz Robert W. Kates Pamela A. Matson Michael R. Botchan Environmental Sciences David W. Russell Hans Joachim Schellnhuber Jennifer A. Doudna and Ecology Microbial Biology Systems Biology Edward D. Korn David M. Karl John M. Coffin Marc W. Kirschner Stephen C. Kowalczykowski Robert May R. John Collier John Kuriyan David W. Schindler Emil C. Gotschlich Systems Neuroscience Michael A. Marletta E. Peter Greenberg Thomas D. Albright Kiyoshi Mizuuchi Evolutionary Biology Diane E. Griffin Robert Desimone Charles M. Radding Francisco J. Ayala Peter M. Howley Fred H. Gage Venkatraman Ramakrishnan May R. Berenbaum Ralph R. Isberg Charles D. Gilbert Tom A. Rapoport Sean B. Carroll Elliott D. Kieff Marcus E. Raichle James A. Wells W. Ford Doolittle Robert A. Lamb Leslie G. Ungerleider William T. Wickner Douglas J. Futuyma Daniel L. Hartl Biophysics and Masatoshi Nei Computational Biology Gene E. Robinson Submission to PNAS David Baker Authors (members and nonmembers) may submit their manuscripts Adriaan Bax Genetics directly to PNAS at www.pnascentral.org. Authors must recommend three William A. Eaton Kathryn V. Anderson appropriate Editorial Board members, three NAS members who are Angela M. Gronenborn Thomas W. Cline expert in the paper’s scientific area, and five qualified referees. No Barry H. Honig Stanley N. Cohen Academy member sponsor is required. Robert Langer Barry Ganetzky PNAS (ISSN-0027-8424) is published weekly in print by the National Academy of Sciences. PNAS STAFF Correspondence: PNAS, 700 11th Street, NW, Suite 450, Washington, DC 20001 USA. E-mail: Publisher Production Manager [email protected]. Kenneth R. Fulton Dana M. Compton Copyright: Volumes 90–105, copyright © 1993–2008 by the National Academy of Sciences of the of Executive Editor Production Staff America, all rights reserved. Volumes 1–89 and 106–107, Diane M. Sullenberger Barbara A. Bacon copyright as a collective work only; author(s) retains Sophie Mohin copyright to individual articles. Requests for Permission: Managing Editor Kelly A. Newton See www.pnas.org/misc/rightperm.shtml for details. Daniel H. Salsbury Kat Rodenhizer Address requests to reproduce material published in Audrey Springer Volumes 1–89 to the original author(s); e-mail Recruiting Editor other requests to [email protected], David Stopak Marketing Manager fax 1-202-334-2739, or PNAS Permissions Editor, Mark Chesnek 700 11th Street, NW, Suite 450, Washington, DC Editorial Staff 20001 USA. Please cite the exact material to be James B. Allison Marketing Staff reprinted and state specifically where it will be used. Josiah W. Armour Jennifer Bradley Photocopies: PNAS is registered with the Copyright Kirti Chadha Clearance Center (CCC), 222 Rosewood Drive, Tom J. Colihan Media Staff Danvers, MA 01923 USA, fax 1-978-750-4470, or Ryan Conley Sola Ayeni-Biu www.copyright.com. Authorization to photocopy Matt Demarest Todd Johnston items for the internal or personal use of specific clients Julia M. Diez d’Aux Jonathan Lifland is granted by the National Academy of Sciences Kathleen E. Dugan Jenny Ruth Morber provided that the proper fee is paid directly to CCC. Microforms: Contact UMI at Meredith C. Jones Ashley Truxon www.umi.com or P.O. Box 1346, Ann Arbor, Nicole Joy MI 48106-1346 USA. Etta Kavanagh Finance Manager Jacob Kendall-Taylor Simone Marshall-Campbell Advertising: Mark Chesnek, 700 11th Street, NW, Suite Sarah Leamy 450, Washington, DC 20001 USA. Phone 1-202-334-2696, Kay McLaughlin Business Staff fax 1-202-334-1346, e-mail [email protected]. Megan Miller Metina Booze Subscriptions: Send payments to PNAS, c/o AIP, P.O. Tom Myers Juanita Culler Box 503284, St. Louis, MO 63150-3284 USA. For Prashant Nair Sara Spizzirri subscription help, e-mail [email protected], phone Jennifer Nelson 1-516-576-2270, or visit www.pnas.org/subscriptions. 2010 N. T. Ngo – fi Rates: US, individual $375 ( rst class delivery available at May B. Piotrowski – a surcharge of $315); non-US, individual $585; Allison Ross – US/non-US, institutional online only, $1,305 7,215. Amy Whitcomb Subscriptions are entered on a calendar-year basis. Exclusive Agent for Subscribers in Japan: USACO Corporation, 17-12 Higashi-Azabu, 2-Chome, Minato-ku, Tokyo 106-0044, Japan. Phone 81 3 3505 3256, fax 81 3 Authorship 3505 6282, e-mail [email protected]. Change of Authorship should be limited to those who have contributed substantially to the fi Address: PNAS, c/o AIP, Suite 1NO1, 2 Huntington work. Authors must indicate their speci c contributions to the published work; Quadrangle, Melville, NY 11747 USA. Phone this information will be published as a footnote to the paper. The corresponding 1-800-344-6902, fax 1-516-349-9704, e-mail [email protected]. author must have obtained permission from all authors for the submission of Please send notification 6 weeks in advance and list the each version of the paper and for any change in authorship. old and new addresses. Claims: Requests for replacement Conflict of Interest copies will not be honored more than 60 days after the All authors, members, referees, and editors must disclose any association that poses a issue date for domestic subscribers and not more than 90 conflict of interest in connection with the manuscript. Authors must acknowledge all days after the issue date for foreign subscribers. Claims funding sources supporting the work. See www.pnas.org/misc/coi.shtml for details. will not be honored for more than two issues per calendar year for the same subscriber. To make a claim, e-mail Supporting Information [email protected] or call 1-800-344-6902. Single Copies: $40 Authors may use Supporting Information to enhance their papers in PNAS by per issue in the US, $50 non-US To order, e-mail providing additional substantive material for online posting, but the print version [email protected] or call 1-800-344-6902. Canadian GST: of the paper must stand on its own merits. Registration Number R-133130880. Cover Images Postmaster: Send address changes to PNAS, c/o AIP, Authors are encouraged to submit scientifically interesting and visually arresting Suite 1NO1, 2 Huntington Quadrangle, Melville, NY images for the cover. 11747 USA. Periodicals postage paid at Washington, DC, and additional mailing offices. Information for Authors Please see the complete Information for Authors, available online at www.pnas.org. PNAS is available online at www.pnas.org. PRINTED IN THE USA PNAS Online PNAS articles are published daily online before print at www.pnas.org in PNAS Early Printed on acid-free paper effective Volume 84, Edition. Issue 1, and on 80% post-consumer recycled paper effective Volume 107, Issue 1. Printed with The articles in PNAS report original research by independent authors and do not soy ink. necessarily represent the views of the National Academies.