The USP1/UAF1 complex promotes double-strand break repair through homologous recombination

J Murai, K Yang, D Dejsuphong, K Hirota… - … and cellular biology, 2011 - Am Soc Microbiol
J Murai, K Yang, D Dejsuphong, K Hirota, S Takeda, AD D'Andrea
Molecular and cellular biology, 2011Am Soc Microbiol
Protein ubiquitination plays a key role in the regulation of a variety of DNA repair
mechanisms. Protein ubiquitination is controlled by the coordinate activity of ubiquitin
ligases and deubiquitinating enzymes (DUBs). The deubiquitinating enzyme USP1
regulates DNA repair and the Fanconi anemia pathway through its association with its
WD40 binding partner, UAF1, and through its deubiquitination of two critical DNA repair
proteins, FANCD2-Ub and PCNA-Ub. To investigate the function of USP1 and UAF1, we …
Abstract
Protein ubiquitination plays a key role in the regulation of a variety of DNA repair mechanisms. Protein ubiquitination is controlled by the coordinate activity of ubiquitin ligases and deubiquitinating enzymes (DUBs). The deubiquitinating enzyme USP1 regulates DNA repair and the Fanconi anemia pathway through its association with its WD40 binding partner, UAF1, and through its deubiquitination of two critical DNA repair proteins, FANCD2-Ub and PCNA-Ub. To investigate the function of USP1 and UAF1, we generated USP1−/−, UAF1−/−/−, and USP1−/− UAF1−/−/− chicken DT40 cell clones. These three clones showed similar sensitivities to chemical cross-linking agents, to a topoisomerase poison, camptothecin, and to an inhibitor of poly (ADP-ribose) polymerase (PARP), indicating that the USP1/UAF1 complex is a regulator of the cellular response to DNA damage. The hypersensitivity to both camptothecin and a PARP inhibitor suggests that the USP1/UAF1 complex promotes homologous recombination (HR)-mediated double-strand break (DSB) repair. To gain insight into the mechanism of the USP1/UAF1 complex in HR, we inactivated the nonhomologous end-joining (NHEJ) pathway in UAF1-deficient cells. Disruption of NHEJ in UAF1-deficient cells restored cellular resistance to camptothecin and the PARP inhibitor. Our results indicate that the USP1/UAF1 complex promotes HR, at least in part by suppressing NHEJ.
American Society for Microbiology