GSBS Student Publications

Title

Xrcc3 is recruited to DNA double strand breaks early and independent of Rad51

GSBS Program

Biochemistry & Molecular Pharmacology

UMMS Affiliation

Graduate School of Biomedical Sciences; Department of Biochemistry and Molecular Pharmacology

Date

9-17-2004

Document Type

Article

Medical Subject Headings

Animals; CHO Cells; Cells, Cultured; Cricetinae; Cricetulus; DNA Damage; DNA Repair; DNA-Binding Proteins; Gamma Rays; Humans; RNA, Small Interfering; Rad51 Recombinase; *Recombination, Genetic

Disciplines

Life Sciences | Medicine and Health Sciences

Abstract

Rad51-mediated homologous recombination (HR) is essential for maintenance of genome integrity. The Xrcc3 protein functions in HR DNA repair, and studies suggest it has multiple roles at different stages in this pathway. Defects in vertebrate XRCC3 result in elevated levels of spontaneous and DNA damage-induced chromosomal abnormalities, as well as increased sensitivity to DNA damaging agents. Formation of DNA damaged-induced nuclear Rad51 foci requires Xrcc3 and the other Rad51 paralog proteins (Rad51B, Rad51C, Rad51D, Xrcc2), thus supporting a model in which an early function of Xrcc3 involves promoting assembly of active Rad51 repair complexes. However, it is not known whether Xrcc3 or other Rad51 paralog proteins accumulate at DNA breaks, and if they do whether their stable association with breaks requires Rad51. Here we report for the first time that Xrcc3 forms distinct foci in human cells and that nuclear Xrcc3 begins to localize at sites of DNA damage within 10 min after radiation treatment. RNAi-mediated knock down of Rad51 has no effect on the DNA damage-induced localization of Xrcc3 to DNA breaks. Our data are consistent with a model in which Xrcc3 associates directly with DNA breaks independent of Rad51, and subsequently facilitates formation of the Rad51 nucleoprotein filament.

Rights and Permissions

Citation: J Cell Biochem. 2004 Oct 15;93(3):429-36. Link to article on publisher's site

DOI of Published Version

10.1002/jcb.20232

Related Resources

Link to article in PubMed

Journal Title

Journal of cellular biochemistry

PubMed ID

15372620