Histone ubiquitination participates in multiple cellular processes, including the DNA damage response. However, the molecular mechanisms involved are not clear. Here, we have identified that RAP80/UIMC1 (ubiquitin interaction motif containing 1), a functional partner of BRCA1, recognizes ubiquitinated histones H2A and H2B. The interaction between RAP80 and ubiquitinated histones H2A and H2B is increased following DNA damage. Since RAP80 facilitates BRCA1's translocation to DNA damage sites, our results indicate that ubiquitinated histones H2A and H2B could be upstream partners of the BRCA1/RAP80 complex in the DNA damage response. Moreover, we have found that RNF8 (ring finger protein 8), an E3 ubiquitin ligase, regulates ubiquitination of both histones H2A and H2B. In RNF8-deficient mouse embryo fibroblasts, ubiquitination of both histones H2A and H2B is dramatically reduced, which abolishes the DNA damage-induced BRCA1 and RAP80 accumulation at damage lesions on the chromatin. Taken together, our results suggest that ubiquitinated histones H2A and H2B may recruit the BRCA1 complex to DNA damage lesions on the chromatin.
SciCrunch is a data sharing and display platform. Anyone can create a custom portal where they can select searchable subsets of hundreds of data sources, brand their web pages and create their community. SciCrunch will push data updates automatically to all portals on a weekly basis. User communities can also add their own data to scicrunch, however this is not currently a free service.