Role of RAD51C and XRCC3 in genetic recombination and DNA repair.
In germ line cells, recombination is required for gene reassortment and proper chromosome segregation at meiosis, whereas in somatic cells it provides an important mechanism for the repair of DNA double-strand breaks. Five proteins (RAD51B, RAD51C, RAD51D, XRCC2, and XRCC3) that share homology with RAD51 recombinase and are known as the RAD51 paralogs are important for recombinational repair, as paralog-defective cell lines exhibit spontaneous chromosomal aberrations, defective DNA repair, and reduced gene targeting. The paralogs form two distinct protein complexes, RAD51B-RAD51C-RAD51D-XRCC2 and RAD51C-XRCC3, but their precise cellular roles remain unknown. Here, we show that, like MLH1, RAD51C localized to mouse meiotic chromosomes at pachytene/diplotene. Using immunoprecipitation and gel filtration analyses, we found that Holliday junction resolvase activity associated tightly and co-eluted with the 80-kDa RAD51C-XRCC3 complex. Taken together, these data indicate that the RAD51C-XRCC3-associated Holliday junction resolvase complex associates with crossovers and may play an essential role in the resolution of recombination intermediates prior to chromosome segregation.
Liu
Yilun
Y
Clare Hall Laboratories, London Research Institute, Cancer Research UK, South Mimms, Hertfordshire EN6 3LD, United Kingdom.
Tarsounas
Madalena
M
O'regan
Paul
P
West
Stephen C
SC
D000818:Animals; D002465:Cell Movement; D047369:Chromatin Immunoprecipitation; D002850:Chromatography, Gel; D002869:Chromosome Aberrations; D053903:DNA Breaks, Double-Stranded; D004260:DNA Repair; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism / Q000502:physiology*; D006367:HeLa Cells; D006801:Humans; D008297:Male; D051379:Mice; D011485:Protein Binding; D011995:Recombination, Genetic
D004268:DNA-Binding Proteins; C448305:RAD51C protein, human; C110901:X-ray repair cross complementing protein 3