XRCC2 is Required for the Formation of Rad51 Foci Induced by Ionizing Radiation and DNA Cross-Linking Agent Mitomycin C

[摘要] XRCC2 protein shares weak amino acid sequence similarity withRad51, which is a central player in homologous recombinationalrepair (HRR). Rad51 proteins assemble at the sites of HRR and formvisible nuclear foci in response to DNA damage.Xrcc2hamster mutant irs1 cells are incapable of forming Rad51 fociafter ionizing irradiation or DNA cross-linking agent mitomycin Ctreatment, though the Rad51 protein level is normal in themutant. The defect can be corrected in anXRCC2transformant. Time course study showed that the irs1 cellsprimarily lacked the early response (2 hours afterirradiation) to form small Rad51 foci (type 1) and later response(8 hours after irradiation) to form large foci (type 2).These results suggested that XRCC2 is essential for the assemblyof the DNA damage-induced Rad51 foci and that XRCC2 may play animportant role in the early stage of HRR.

[学科分类] 基础医学