RAD51 separation of function mutation disables replication fork maintenance but preserves DSB repair

• Published in: iScience Vol. 27; no. 4; p. 109524
• Main Authors: Son, Mi Young, Belan, Ondrej, Spirek, Mario, Cibulka, Jakub, Nikulenkov, Fedor, Kim, You Young, Hwang, Sunyoung, Myung, Kyungjae, Montagna, Cristina, Kim, Tae Moon, Krejci, Lumir, Hasty, Paul
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 19.04.2024; Elsevier
• Subjects: Genetics; Molecular biology; Molecular interaction; Properties of biomolecules; Genetics; Molecular interaction; Molecular biology; Properties of biomolecules
• ISSN: 2589-0042; 2589-0042
• DOI: 10.1016/j.isci.2024.109524

Homologous recombination (HR) protects replication forks (RFs) and repairs DNA double-strand breaks (DSBs). Within HR, BRCA2 regulates RAD51 via two interaction regions: the BRC repeats to form filaments on single-stranded DNA and exon 27 (Ex27) to stabilize the filament. Here, we identified a RAD51 S181P mutant that selectively disrupted the RAD51-Ex27 association while maintaining interaction with BRC repeat and proficiently forming filaments capable of DNA binding and strand invasion. Interestingly, RAD51 S181P was defective for RF protection/restart but proficient for DSB repair. Our data suggest that Ex27-mediated stabilization of RAD51 filaments is required for the protection of RFs, while it seems dispensable for the repair of DSBs. [Display omitted] •RAD51 SP mutant is selectively deficient in Ex27-binding•Ex27 failed to protect SP filaments against BRC4 but does not affect ATP hydrolysis•RAD51 SP is proficient for HR-mediated DSB repair but fails to protect RFs•Loss of the RAD51-Ex27 interaction results in increased Robertsonian translocations Properties of biomolecules; Genetics; Molecular biology; Molecular interaction