Non-enzymatic roles of human RAD51 at stalled replication forks

• Published in: Nature communications Vol. 10; no. 1; pp. 4410 - 11
• Main Authors: Mason, Jennifer M., Chan, Yuen-Ling, Weichselbaum, Ralph W., Bishop, Douglas K.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 27-09-2019; Nature Publishing Group; Nature Portfolio
• Subjects: 13; 13/106; 13/89; 14; 14/1; 14/63; 631/337/1427/2190; 631/337/151/2356; 64; 82/80; 82/83; Binding sites; Deoxyribonucleic acid; DNA; DNA - chemistry; DNA - genetics; DNA - metabolism; DNA Replication; DNA-Binding Proteins - genetics; DNA-Binding Proteins - metabolism; Enzymatic activity; Exchanging; Genomes; Humanities and Social Sciences; Humans; Models, Genetic; MRE11 protein; multidisciplinary; Mutation; Nucleic Acid Conformation; Proteins; Rad51 Recombinase - genetics; Rad51 Recombinase - metabolism; Recombination; Regression models; Replication; Replication forks; Roles; Science; Science (multidisciplinary)
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-019-12297-0

The central recombination enzyme RAD51 has been implicated in replication fork processing and restart in response to replication stress. Here, we use a separation-of-function allele of RAD51 that retains DNA binding, but not D-loop activity, to reveal mechanistic aspects of RAD51’s roles in the response to replication stress. Here, we find that cells lacking RAD51’s enzymatic activity protect replication forks from MRE11-dependent degradation, as expected from previous studies. Unexpectedly, we find that RAD51’s strand exchange activity is not required to convert stalled forks to a form that can be degraded by DNA2. Such conversion was shown previously to require replication fork regression, supporting a model in which fork regression depends on a non-enzymatic function of RAD51. We also show RAD51 promotes replication restart by both strand exchange-dependent and strand exchange-independent mechanisms.
RAD51 has been implicated in replication fork processing and restart in response to replication stress. Here, authors reveal mechanistic aspects of non-enzymatic roles of RAD51 for fork reversal and cooperation with FBH1.