Rad51C deficiency destabilizes XRCC3, impairs recombination and radiosensitizes S/G2-phase cells
The highly conserved Rad51 protein plays an essential role in repairing DNA damage through homologous recombination. In vertebrates, five Rad51 paralogs (Rad51B, Rad51C, Rad51D, XRCC2, XRCC3) are expressed in mitotically growing cells, and are thought to play mediating roles in homologous recombination, though their precise functions remain unclear. Here we report the use of RNA interference to deplete expression of Rad51C protein in human HT1080 and HeLa cells. In HT1080 cells, depletion of Rad51C by small interfering RNA caused a significant reduction of frequency in homologous recombination. The level of XRCC3 protein was also sharply reduced in Rad51C-depleted HeLa cells, suggesting that XRCC3 is dependent for its stability upon heterodimerization with Rad51C. In addition, Rad51C-depleted HeLa cells showed hypersensitivity to the DNA cross-linking agent mitomycin C, and moderately increased sensitivity to ionizing radiation. Importantly, the radiosensitivity of Rad51C-deficient HeLa cells was evident in S and G{sub 2}/M phases of the cell cycle but not in G{sub 1} phase. Together, these results provide direct cellular evidence for the importance of human Rad51C in homologous recombinational repair.
- Research Organization:
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
- Sponsoring Organization:
- USDOE Director. Office of Science. Office of Biological and Environmental Research. Life Sciences Division. Contracts DE-AC03-76SF00098 and DE-FG03-02ER63309; US Department of Defense Grant DAMD17-02-1-0439, US Army Breast Cancer Research Program Postdoctoral Fellowship Award DAMD17-00-1-0367, National Institutes of Health Grants GM030990 and CA092584; California Breast Cancer Research Program Grant 7KB-0019 (US)
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 838067
- Report Number(s):
- LBNL-55027; R&D Project: 80SC01; TRN: US200507%%297
- Journal Information:
- Journal of Biological Chemistry, Vol. 279, Issue 40; Other Information: Submitted to Journal of Biological Chemistry: Volume 279, No.40; Journal Publication Date: 10/01/2004; PBD: 1 May 2004
- Country of Publication:
- United States
- Language:
- English
Similar Records
Disparate requirements for the Walker A and B ATPase motifs ofhuman RAD51D in homologous recombination
Nuclear localization of Rad51B is independent of BRCA2