Visualizing locus-specific sister chromatid exchange reveals differential patterns of replication stress-induced fragile site breakage.

ABSTRACT: Chromosomal fragile sites are genomic loci sensitive to replication stress which accumulate high levels of DNA damage, and are frequently mutated in cancers. Fragile site damage is thought to arise from the aberrant repair of spontaneous replication stress, however successful fragile site repair cannot be calculated using existing techniques. Here, we report a new assay measuring recombination-mediated repair at endogenous genomic loci by combining a sister chromatid exchange (SCE) assay with fluorescent in situ hybridization (SCE-FISH). Using SCE-FISH, we find that endogenous and exogenous replication stress generated unrepaired breaks and SCEs at fragile sites. We also find that distinct sources of replication stress induce distinct patterns of breakage: ATR inhibition induces more break

SUBMITTER: Waisertreiger I 

PROVIDER: S-EPMC7002298 | biostudies-literature | 2020 Feb

REPOSITORIES: biostudies-literature