A Dominant Mutation in Human RAD51 Reveals Its Function in DNA Interstrand Crosslink Repair Independent of Homologous Recombination

• Published in: Molecular cell Vol. 59; no. 3; pp. 478 - 490
• Main Authors: Wang, Anderson T., Kim, Taeho, Wagner, John E., Conti, Brooke A., Lach, Francis P., Huang, Athena L., Molina, Henrik, Sanborn, Erica M., Zierhut, Heather, Cornes, Belinda K., Abhyankar, Avinash, Sougnez, Carrie, Gabriel, Stacey B., Auerbach, Arleen D., Kowalczykowski, Stephen C., Smogorzewska, Agata
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 06.08.2015
• Subjects: adenosinetriphosphatase; Cell Survival; Cross-Linking Reagents; crosslinking; DNA; DNA - metabolism; DNA Helicases - metabolism; DNA Repair; Exodeoxyribonucleases - metabolism; Fanconi Anemia - genetics; Fanconi Anemia - metabolism; Female; Genomic Instability; HEK293 Cells; heterozygosity; Heterozygote; homologous recombination; Humans; Infant; mutants; Mutation; patients; phenotype; Rad51 Recombinase - genetics; Rad51 Recombinase - metabolism; RecQ Helicases - metabolism; Replication Protein A - metabolism; Werner Syndrome Helicase
• ISSN: 1097-2765; 1097-4164
• DOI: 10.1016/j.molcel.2015.07.009

Repair of DNA interstrand crosslinks requires action of multiple DNA repair pathways, including homologous recombination. Here, we report a de novo heterozygous T131P mutation in RAD51/FANCR, the key recombinase essential for homologous recombination, in a patient with Fanconi anemia-like phenotype. In vitro, RAD51-T131P displays DNA-independent ATPase activity, no DNA pairing capacity, and a co-dominant-negative effect on RAD51 recombinase function. However, the patient cells are homologous recombination proficient due to the low ratio of mutant to wild-type RAD51 in cells. Instead, patient cells are sensitive to crosslinking agents and display hyperphosphorylation of Replication Protein A due to increased activity of DNA2 and WRN at the DNA interstrand crosslinks. Thus, proper RAD51 function is important during DNA interstrand crosslink repair outside of homologous recombination. Our study provides a molecular basis for how RAD51 and its associated factors may operate in a homologous recombination-independent manner to maintain genomic integrity. [Display omitted] •A dominant-negative mutation in RAD51 is identified in Fanconi anemia-like patient•RAD51 T131P-expressing cells are ICL repair defective but HR proficient•RAD51 T131P has unregulated ATPase activity poisoning wild-type RAD51•Defective RAD51 function results in DNA2/WRN-dependent degradation of DNA Defects in DNA interstrand crosslink (ICL) repair have detrimental consequences, including stem cell failure and tumorigenesis. Wang et al. uncover a new subtype of Fanconi anemia, FA-R, in which a de novo negative co-dominant RAD51 (FANCR) mutation results in ICL repair defect without affecting RAD51-dependent homologous recombination.