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

Mol Cell. 2015 Aug 6;59(3):478-90. doi: 10.1016/j.molcel.2015.07.009.

Abstract

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.

Publication types

  • Case Reports
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Survival
  • Cross-Linking Reagents
  • DNA / metabolism*
  • DNA Helicases / metabolism
  • DNA Repair*
  • Exodeoxyribonucleases / metabolism
  • Fanconi Anemia / genetics*
  • Fanconi Anemia / metabolism
  • Female
  • Genomic Instability
  • HEK293 Cells
  • Heterozygote
  • Humans
  • Infant
  • Mutation
  • Rad51 Recombinase / genetics*
  • Rad51 Recombinase / metabolism*
  • RecQ Helicases / metabolism
  • Replication Protein A / metabolism*
  • Werner Syndrome Helicase

Substances

  • Cross-Linking Reagents
  • RPA1 protein, human
  • Replication Protein A
  • DNA
  • RAD51 protein, human
  • Rad51 Recombinase
  • Exodeoxyribonucleases
  • DNA Helicases
  • DNA2 protein, human
  • RecQ Helicases
  • WRN protein, human
  • Werner Syndrome Helicase