title: The USP1/UAF1 complex promotes double-strand break repair through homologous recombination.
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.
authors.affiliation: Department of Radiation Genetics, Kyoto University Graduate School of Medicine, Yoshida Konoe, Sakyo-ku, Kyoto 606-8501, Japan.
authors.forename: Junko
authors.initials: J
authors.lastname: Murai
authors.forename: Kailin
authors.initials: K
authors.lastname: Yang
authors.forename: Donniphat
authors.initials: D
authors.lastname: Dejsuphong
authors.forename: Kouji
authors.initials: K
authors.lastname: Hirota
authors.forename: Shunichi
authors.initials: S
authors.lastname: Takeda
authors.forename: Alan D
authors.initials: AD
authors.lastname: D'Andrea
mesh_terms: D000818:Animals; D029681:Arabidopsis Proteins; D002166:Camptothecin / Q000378:metabolism; D002460:Cell Line; D002645:Chickens; D004247:DNA / Q000235:genetics / Q000378:metabolism; D053903:DNA Breaks, Double-Stranded; D004260:DNA Repair; D010450:Endopeptidases / Q000235:genetics / Q000378:metabolism*; D004843:Epistasis, Genetic; D052236:Fanconi Anemia Complementation Group D2 Protein / Q000235:genetics / Q000378:metabolism; D055785:Gene Knockdown Techniques; D006801:Humans; D009097:Multienzyme Complexes / Q000235:genetics / Q000378:metabolism*; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D011995:Recombination, Genetic; D059004:Topoisomerase I Inhibitors / Q000378:metabolism; D064570:Ubiquitin-Specific Proteases
chemical_list: D029681:Arabidopsis Proteins; D052236:Fanconi Anemia Complementation Group D2 Protein; D009097:Multienzyme Complexes; D009687:Nuclear Proteins; D059004:Topoisomerase I Inhibitors; D004247:DNA; D010450:Endopeptidases; C579228:USP1 protein, human; D064570:Ubiquitin-Specific Proteases; D002166:Camptothecin