Mechanism of BRCA1-BARD1 function in DNA end resection and DNA protection

• 成果类型: Article
• 署名作者: Ceppi, Ilaria; Dello Stritto, Maria Rosaria; Muetze, Martin; Braunshier, Stefan; Mengoli, Valentina; Reginato, Giordano; Ho My Phuc Vo; Jimeno, Sonia; Acharya, Ananya; Roy, Megha; Sanchez, Aurore; Halder, Swagata; Howard, Sean Michael; Guerois, Raphael; Huertas, Pablo; Noordermeer, Sylvie M.; Seidel, Ralf; Cejka, Petr
• 署名单位: Universita della Svizzera Italiana; Leipzig University; Leiden University; Leiden University Medical Center (LUMC); University of Sevilla; Consejo Superior de Investigaciones Cientificas (CSIC); Universidad Pablo de Olavide; University of Sevilla; CSIC - Centro Andaluz de Biologia Molecular y Medicina Regenerativa (CABIMER); Centre National de la Recherche Scientifique (CNRS); Universite Paris Saclay; Universite PSL; UNICANCER; Institut Curie; Centre National de la Recherche Scientifique (CNRS); Sorbonne Universite; CNRS - National Institute for Biology (INSB); Boise State University
• 刊物名称: Nature
• ISSN/ISSBN: 0028-5558
• DOI: 10.1038/s41586-024-07909-9
• 发表日期: 2024-10-10
• 页码: 492-+
• 关键词: brca1-deficient cells; complex-formation; motor-activity; brca1; ctip; protein; repair; range; phosphorylation; helicase

摘要

DNA double-strand break (DSB) repair by homologous recombination is initiated by DNA end resection, a process involving the controlled degradation of the 5-terminated strands at DSB sites(1,2). The breast cancer suppressor BRCA1-BARD1 not only promotes resection and homologous recombination, but it also protects DNA upon replication stress(1,3-9). BRCA1-BARD1 counteracts the anti-resection and pro-non-homologous end-joining factor 53BP1, but whether it functions in resection directly has been unclear(10-16). Using purified recombinant proteins, we show here that BRCA1-BARD1 directly promotes long-range DNA end resection pathways catalysed by the EXO1 or DNA2 nucleases. In the DNA2-dependent pathway, BRCA1-BARD1 stimulates DNA unwinding by the Werner or Bloom helicase. Together with MRE11-RAD50-NBS1 and phosphorylated CtIP, BRCA1-BARD1 forms the BRCA1-C complex(17,18), which stimulates resection synergistically to an even greater extent. A mutation in phosphorylated CtIP (S327A), which disrupts its binding to the BRCT repeats of BRCA1 and hence the integrity of the BRCA1-C complex(19-21), inhibits resection, showing that BRCA1-C is a functionally integrated ensemble. Whereas BRCA1-BARD1 stimulates resection in DSB repair, it paradoxically also protects replication forks from unscheduled degradation upon stress, which involves a homologous recombination-independent function of the recombinase RAD51 (refs. (4-6,8)). We show that in the presence of RAD51, BRCA1-BARD1 instead inhibits DNA degradation. On the basis of our data, the presence and local concentration of RAD51 might determine the balance between the pronuclease and the DNA protection functions of BRCA1-BARD1 in various physiological contexts.