title: XRCC1 is required for DNA single-strand break repair in human cells.
abstract: The X-ray repair cross complementing 1 (XRCC1) protein is required for viability and efficient repair of DNA single-strand breaks (SSBs) in rodents. XRCC1-deficient mouse or hamster cells are hypersensitive to DNA damaging agents generating SSBs and display genetic instability after such DNA damage. The presence of certain polymorphisms in the human XRCC1 gene has been associated with altered cancer risk, but the role of XRCC1 in SSB repair (SSBR) in human cells is poorly defined. To elucidate this role, we used RNA interference to modulate XRCC1 protein levels in human cell lines. A reduction in XRCC1 protein levels resulted in decreased SSBR capacity as measured by the comet assay and intracellular NAD(P)H levels, hypersensitivity to the cell killing effects of the DNA damaging agents methyl methanesulfonate (MMS), hydrogen peroxide and ionizing radiation and enhanced formation of micronuclei following exposure to MMS. Lowered XRCC1 protein levels were also associated with a significant delay in S-phase progression after exposure to MMS. These data clearly demonstrate that XRCC1 is required for efficient SSBR and genomic stability in human cells.
authors.affiliation: DNA Repair Team, International Agency for Research on Cancer F-69372 Lyon, France.
authors.forename: Reto
authors.initials: R
authors.lastname: Brem
authors.forename: Janet
authors.initials: J
authors.lastname: Hall
mesh_terms: D002453:Cell Cycle / Q000187:drug effects; D045744:Cell Line, Tumor; D002470:Cell Survival; D020552:Comet Assay; D004249:DNA Damage; D004260:DNA Repair; D004277:DNA, Single-Stranded / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000502:physiology*; D006801:Humans; D008741:Methyl Methanesulfonate / Q000633:toxicity; D015162:Micronucleus Tests; D009249:NADP / Q000378:metabolism; D034622:RNA Interference; D000076105:X-ray Repair Cross Complementing Protein 1
chemical_list: D004277:DNA, Single-Stranded; D004268:DNA-Binding Proteins; D000076105:X-ray Repair Cross Complementing Protein 1; C000619371:XRCC1 protein, human; C000619352:Xrcc1 protein, mouse; D009249:NADP; D008741:Methyl Methanesulfonate