Cellular redistribution of Rad51 in response to DNA damage: novel role for Rad51C.
Article Details
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Gildemeister OS, Sage JM, Knight KL
Cellular redistribution of Rad51 in response to DNA damage: novel role for Rad51C.
J Biol Chem. 2009 Nov 13;284(46):31945-52. doi: 10.1074/jbc.M109.024646. Epub 2009 Sep 26.
- PubMed ID
- 19783859 [ View in PubMed]
- Abstract
Exposure of cells to DNA-damaging agents results in a rapid increase in the formation of subnuclear complexes containing Rad51. To date, it has not been determined to what extent DNA damage-induced cytoplasmic to nuclear transport of Rad51 may contribute to this process. We have analyzed subcellular fractions of HeLa and HCT116 cells and found a significant increase in nuclear Rad51 levels following exposure to a modest dose of ionizing radiation (2 grays). We also observed a DNA damage-induced increase in nuclear Rad51 in the Brca2-defective cell line Capan-1. To address a possible Brca2-independent mechanism for Rad51 nuclear transport, we analyzed subcellular fractions for two other Rad51-interacting proteins, Rad51C and Xrcc3. Rad51C has a functional nuclear localization signal, and although we found that the subcellular distribution of Xrcc3 was not significantly affected by DNA damage, there was a damage-induced increase in nuclear Rad51C. Furthermore, RNA interference-mediated depletion of Rad51C in HeLa and Capan-1 cells resulted in lower steady-state levels of nuclear Rad51 as well as a diminished DNA damage-induced increase. Our results provide important insight into the cellular regulation of Rad51 nuclear entry and a role for Rad51C in this process.