Replication Stress-Induced Chromosome Breakage Is Correlated with Replication Fork Progression and Is Preceded by Single-Stranded DNA Formation

G3: Genes, Genomes, Genetics

Wenyi Feng²  Bonita J. Brewer¹  Sara C. Di Rienzi¹  M. K. Raghuraman¹ 

[1] Department of Genome Sciences, University of Washington, Seattle, Washington 98195Department of Genome Sciences, University of Washington, Seattle, Washington 98195Department of Genome Sciences, University of Washington, Seattle, Washington 98195;Department of Genome Sciences, University of Washington, Seattle, Washington 98195Department of Biochemistry and Molecular Biology, Upstate Medical University, Syracuse, New York 13210Department of Genome Sciences, University of Washington, Seattle, Washington 98195Department of Genome Sciences, University of Washington, Seattle, Washington 98195Department of Biochemistry and Molecular Biology, Upstate Medical University, Syracuse, New York 13210Department of Biochemistry and Molecular Biology, Upstate Medical University, Syracuse, New York 13210Department of Genome Sciences, University of Washington, Seattle, Washington 98195Department of Biochemistry and Molecular Biology, Upstate Medical University, Syracuse, New York 13210

关键词: chromosome fragile sites;    double strand breaks;    mec1;    replication checkpoint;    single-stranded DNA;   

DOI  :  10.1534/g3.111.000554

学科分类：生物科学（综合）

来源: Genetics Society of America

【 摘 要 】

Chromosome breakage as a result of replication stress has been hypothesized to be the direct consequence of defective replication fork progression, or “collapsed” replication forks. However, direct and genome-wide evidence that collapsed replication forks give rise to chromosome breakage is still lacking. Previously we showed that a yeast replication checkpoint mutant mec1-1, after transient exposure to replication impediment imposed by hydroxyurea (HU), failed to complete DNA replication, accumulated single-stranded DNA (ssDNA) at the replication forks, and fragmented its chromosomes. In this study, by following replication fork progression genome-wide via ssDNA detection and by direct mapping of chromosome breakage after HU exposure, we have tested the hypothesis that the chromosome breakage in mec1 cells occurs at collapsed replication forks. We demonstrate that sites of chromosome breakage indeed correlate with replication fork locations. Moreover, ssDNA can be detected prior to chromosome breakage, suggesting that ssDNA accumulation is the common precursor to double strand breaks at collapsed replication forks.

【 授权许可】

Unknown