Replication stress induces specific enrichment of RECQ1 at common fragile sites FRA3B and FRA16D

Molecular Cancer

Research

Swetha Parvathaneni¹  Sudha Sharma¹  Xing Lu¹  Ashish Lal²  Toshifumi Hara² 

[1] Department of Biochemistry and Molecular Biology, College of Medicine, Howard University, 520 W Street, NW, 20059, Washington, DC, USA;Genetics Branch, National Cancer Institute, National Institutes of Health, 20892, Bethesda, MD, USA;

关键词: RecQ;    Helicase;    Replication stress;    DNA repair;    DNA damage;    Genomic instability;   

DOI  :  10.1186/1476-4598-12-29

 received in 2013-02-04, accepted in 2013-04-10,  发布年份 2013

来源: Springer

【 摘 要 】

BackgroundStalled replication forks at common fragile sites are a major cause of genomic instability. RecQ helicases, a highly conserved family of DNA-unwinding enzymes, are believed to ease ‘roadblocks’ that pose challenge to replication fork progression. Among the five known RecQ homologs in humans, functions of RECQ1, the most abundant of all, are poorly understood. We previously determined that RECQ1 helicase preferentially binds and unwinds substrates that mimic DNA replication/repair intermediates, and interacts with proteins involved in DNA replication restart mechanisms.MethodWe have utilized chromatin immunoprecipitation followed by quantitative real-time PCR to investigate chromatin interactions of RECQ1 at defined genetic loci in the presence or absence of replication stress. We have also tested the sensitivity of RECQ1-depleted cells to aphidicolin induced replication stress.ResultsRECQ1 binds to the origins of replication in unperturbed cells. We now show that conditions of replication stress induce increased accumulation of RECQ1 at the lamin B2 origin in HeLa cells. Consistent with a role in promoting fork recovery or repair, RECQ1 is specifically enriched at two major fragile sites FRA3B and FRA16D where replication forks have stalled following aphidicolin treatment. RECQ1-depletion results in attenuated checkpoint activation in response to replication stress, increased sensitivity to aphidicolin and chromosomal instability.ConclusionsGiven a recent biochemical observation that RECQ1 catalyzes strand exchange on stalled replication fork structures in vitro, our results indicate that RECQ1 facilitates repair of stalled or collapsed replication forks and preserves genome integrity. Our findings provide the first evidence of a crucial role for RECQ1 at naturally occurring fork stalling sites and implicate RECQ1 in mechanisms underlying common fragile site instability in cancer.

【 授权许可】

Unknown   
© Lu et al.; licensee BioMed Central Ltd. 2013. This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.