Study Shows DNA Acts Like √”Magic Rings√• Trick

Study shows DNA acts like Ã”magic ringsÃ• trick Davis Enterprise Page 1 of 5

Sunday, June 16, 2013 YOLO COUNTY NEWS 99 CENTS

Study shows DNA acts like Recent Posts Ã”magic ringsÃ• trick A big thanks to the dads Print edition, Sunday, June 16, 2013 By Andy Fell October 19, 2010 | Leave Comment River Cats shut down Tacoma Wire sports briefs: Bruins tie Cup finals in OT Special to the Enterprise Sports briefs: Hicks injured at UCLA football camp; to miss final DHS season A new study from UC Davis shows how, like a conjuring trick with interlocking rings, two interlocked pieces of DNA are separated after DNA is copied or repaired.

While reconstituting the DNA repair system of yeast in a test tube, the researchers found that a complex of proteins called Search Sgs1, Top3 and Rmi1 allow one DNA strand to open and the other to pass through. HOME ÒThis protein complex does what magicians do,Ó said lead NEWS researcher Stephen Kowalczykowski, distinguished professor FORUM of microbiology in the UCD College of Biological Sciences and SPORTS a member of the UCD Cancer Center.

FEATURES The finding was published online Oct. 10 in the journal Nature ARTS Structural and Molecular Biology.

BUSINESS The discovery may hold answers to a human disease called OBITUARIES BloomÕs syndrome, which increases the risk of cancer, among COMICS other health problems. Sgs1 appears to be the yeast equivalent of the human protein tied to BloomÕs syndrome, GALLERY Kowalczykowski said. CLASSIFIEDS DNA suffers damage all the time both from outside influences, ADVERTISERS such as radiation or chemicals, and also from normal cellular CONTACT US processes. Unrepaired, DNA damage can lead to cancer or birth defects. Several genes linked to a high risk of cancer, such as the Òbreast cancer geneÓ BRCA2, have turned out to be involved in DNA repair.

When damage crosses both strands of the DNA double helix, a sophisticated repair process is activated that uses the same DNA sequence on the matching chromosome. One of the 1,892 2,299 strands is stripped back, leaving an exposed single strand. The matching chromosome is brought alongside and partly unwound, and acts as a template to repair the broken piece.

At this point, the two chromosomes are intact but attached at two points through structures called ÒHolliday junctions,Ó where DNA strands from the two chromosomes cross each other. To finish the process, the chromosomes have to separate Ñ like the magicianÕs interlocking rings, one has to pass through the other.

Working with a mix of yeast proteins and DNA in a test tube, Kowalczykowski and his colleagues showed that the Sgs1/Top3/Rmi1 protein complex attaches to the paired DNA at the Holliday junction, opens up a gap in one strand and passes the other through it, allowing the two chromosomes to separate cleanly and dissolving the junction.

Patients with BloomÕs syndrome show extensive swapping of chunks of DNA between chromosomes. Kowalczykowski is convinced that the problem is due to poor dissolution of Holliday junctions in these patients.

http://www.davisenterprise.com/Archived-Stories-0/study-shows-dna-acts-like-magic-ring... 6/16/2013 Study shows DNA acts like Ã”magic ringsÃ• trick Davis Enterprise Page 2 of 5

Holliday junctions were only definitively shown to exist in mitotically dividing cells in April this year, in a paper by UCD researchers Malgosia Bzymek and Neil Hunter, associate professor of microbiology.

KowalczykowskiÕs collaborators in the new study were UCS postdoctoral researchers Petr Cejka and Jody Plank, and Oxford University scientists Csanad Bachrati and Ian Hickson.

In a paper published in Nature last month, KowalczykowskiÕs lab also showed that the Sgs1/Top3/Rmi1 complex of proteins is involved in the first step of DNA repair Ñ cleaning the broken end to leave a single strand of DNA.

The research was funded by the National Institutes of Health, the Swiss National Science Foundation and Cancer Research UK.

Ñ UC Davis News Service

Andy Fell

HOME

NEWS

FORUM View all my stories Email Me

SPORTS FEATURES LEAVE A COMMENT ARTS

BUSINESS

OBITUARIES Discussion | No comments

COMICS The Davis Enterprise does not necessarily condone the comments here, nor GALLERY does it review every post. Read our full policy

CLASSIFIEDS

ADVERTISERS

News

Dan Wolk, a Davis politician, father, sets out to FamiliesFirst CEO vows to battle license 1,892 2,299 ‘restore the California dream’ revocation as new allegations raised By Brett Johnson | From Page: A1 | Gallery By Lauren Keene | From Page: A1 | Gallery

Juneteenth celebrates 150 years of freedom State budget gives lift to UCD, students By Brett Johnson | From Page: A1 By Cory Golden | From Page: A1

A sea turtle in memory of a mother Reformists dance in streets after Iranian vote By Anne Ternus-Bellamy | From Page: A1 | Gallery By The Associated Press | From Page: A2

Firefighters advance containment on Colo. State lawmakers expand Medicaid wildfire By The Associated Press | From Page: A2 By The Associated Press | From Page: A2

Woodland shooting victim identified Bob Dunning: It’s a four-horse race in the 4th By Lauren Keene | From Page: A2 District By Bob Dunning | From Page: A2, 2 Comments

Family pride Volunteers needed for Livestrong Challenge By Sue Cockrell | From Page: A3 By Enterprise staff | From Page: A3

http://www.davisenterprise.com/Archived-Stories-0/study-shows-dna-acts-like-magic-ring... 6/16/2013 Study shows DNA acts like Ã”magic ringsÃ• trick Davis Enterprise Page 3 of 5

Prep program teaches green jobs, life skills Cabrillo Club hosts scholarship picnic By McNaughton Newspapers | From Page: A3 | Gallery By Enterprise staff | From Page: A4

Solar cooker demonstrations planned Visit Sutter market on Thursdays By Enterprise staff | From Page: A4 | Gallery By Special to The Enterprise | From Page: A4

Amateur radio groups compete to reach around Graduation DVDs available through Davis the world Media Access By Enterprise staff | From Page: A4 By Special to The Enterprise | From Page: A4

Pleasants Creek is topic of June’s CreekSpeak Yolo Hospice: Volunteers reap rich rewards By Special to The Enterprise | From Page: A7 | Gallery By Mary Odbert | From Page: A8

Remote-controlled gliders face off at soaring ‘Yappy Hour’ a class for puppies, owners challenge By Cory Golden | From Page: A12 By Enterprise staff | From Page: A8

Forum Search

HOME The rent includes free humiliation May my existence be the reason for an outline of By Special to The Enterprise | From Page: B5 NEWS bullets By Debra DeAngelo | From Page: A6 FORUM SPORTS A big thanks to the dads Should you research your health on your own? FEATURES By Special to The Enterprise | From Page: A6 By Marion Franck | From Page: A6

ARTS Fat cats and portly pups IRS screeners on the right track BUSINESS By Keith Rode, DVM | From Page: A6 By Letters to the Editor | From Page: A10 OBITUARIES COMICS Obama terror policies are a joke Tom Meyer cartoon By Letters to the Editor | From Page: A10 By Debbie Davis | From Page: A10 GALLERY CLASSIFIEDS Garamendi’s message: Spend more Village Homes water wall clarified ADVERTISERS By Letters to the Editor | From Page: A10, 3 Comments By Letters to the Editor | From Page: A10 CONTACT US Celebrate family and freedom A coop crawl eggsperience By Letters to the Editor | From Page: A10 By Letters to the Editor | From Page: A10

We are accountable for these children Please assure our constitutional rights By Debbie Davis | From Page: A10, 1 Comment By Special to The Enterprise | From Page: A11

Juneteenth: Remembering the promise of What do you think? What is the coolest thing 1,892 2,299 citizenship your dad has taught you? By Desmond Jolly | From Page: A11 | Gallery By Zoe Juanitas | From Page: A11

Sports

River Cats shut down Tacoma Gold Rush Randonnée ride is four years in the By Will Bellamy | From Page: B1 making By Special to The Enterprise | From Page: B1 | Gallery

Magical 1960 Pirates’ season chronicled by Livestrong Challenge cycling event to draw Davis man’s new book hundreds By Bruce Gallaudet | From Page: B1 | Gallery By Special to The Enterprise | From Page: B1

Sports briefs: Hicks injured at UCLA football Wire sports briefs: Bruins tie Cup finals in OT camp; to miss final DHS season By The Associated Press | From Page: B10 By Enterprise staff | From Page: B2 | Gallery

http://www.davisenterprise.com/Archived-Stories-0/study-shows-dna-acts-like-magic-ring... 6/16/2013 Study shows DNA acts like Ã”magic ringsÃ• trick Davis Enterprise Page 4 of 5

Features

Arts

Business

Disappointing reports push down stocks Flea market finds home for Father’s Day By The Associated Press | From Page: A5 weekend By Wendy Weitzel | From Page: A5

Save Mart receives State Fair’s Golden Bear Travis Credit Union appoints new executive VP Award By Enterprise staff | From Page: A5 Search By Enterprise staff | From Page: A5

HOME

NEWS . FORUM SPORTS Obituaries FEATURES

ARTS Juan Reynoso Dias By Special to The Enterprise | From Page: A4 BUSINESS

OBITUARIES COMICS . GALLERY CLASSIFIEDS Comics ADVERTISERS

Zits Mother Goose & Grimm By Creator | From Page: B8 By Creator | From Page: B8

Baby Blues Classic Peanuts By Creator | From Page: B8 By Creator | From Page: B8 1,892 2,299 Arlo & Janis Mutts By Creator | From Page: B8 By Creator | From Page: B8

Rose is Rose Close To Home & Real Life Adventures By Creator | From Page: B8 By Creator | From Page: B8

Frazz For Better or For Worse By Creator | From Page: B8 By Creator | From Page: B8

Get Fuzzy The Wizard of Id By Creator | From Page: B8 By Creator | From Page: B8

Live Visitors’ Guide

Timeline Real Estate Review

http://www.davisenterprise.com/Archived-Stories-0/study-shows-dna-acts-like-magic-ring... 6/16/2013 Study shows DNA acts like Ã”magic ringsÃ• trick Davis Enterprise Page 5 of 5

Commentary Open Houses Map

Print Edition Last Chance Rental Guide

Facebook Picnic Day

Twitter Readers’ Choice 2013

Home for the Holidays

Welcome: Only in Davis

Search Welcome: Our community HOME

NEWS

FORUM Welcome: On campus SPORTS

FEATURES Welcome: On the go ARTS

BUSINESS

OBITUARIES Discover Downtown Davis COMICS

GALLERY Stroll Through History CLASSIFIEDS

ADVERTISERS

1,892 2,299

http://www.davisenterprise.com/Archived-Stories-0/study-shows-dna-acts-like-magic-ring... 6/16/2013