Roles of XRCC2, RAD51B and RAD51D in RAD51-independent SSA recombination

PLoS Genet. 2013 Nov;9(11):e1003971. doi: 10.1371/journal.pgen.1003971. Epub 2013 Nov 21.

Abstract

The repair of DNA double-strand breaks by recombination is key to the maintenance of genome integrity in all living organisms. Recombination can however generate mutations and chromosomal rearrangements, making the regulation and the choice of specific pathways of great importance. In addition to end-joining through non-homologous recombination pathways, DNA breaks are repaired by two homology-dependent pathways that can be distinguished by their dependence or not on strand invasion catalysed by the RAD51 recombinase. Working with the plant Arabidopsis thaliana, we present here an unexpected role in recombination for the Arabidopsis RAD51 paralogues XRCC2, RAD51B and RAD51D in the RAD51-independent single-strand annealing pathway. The roles of these proteins are seen in spontaneous and in DSB-induced recombination at a tandem direct repeat recombination tester locus, both of which are unaffected by the absence of RAD51. Individual roles of these proteins are suggested by the strikingly different severities of the phenotypes of the individual mutants, with the xrcc2 mutant being the most affected, and this is confirmed by epistasis analyses using multiple knockouts. Notwithstanding their clearly established importance for RAD51-dependent homologous recombination, XRCC2, RAD51B and RAD51D thus also participate in Single-Strand Annealing recombination.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Arabidopsis / genetics
  • Arabidopsis Proteins / genetics*
  • DNA Breaks, Double-Stranded
  • DNA Repair / genetics
  • DNA-Binding Proteins / genetics*
  • Homologous Recombination / genetics*
  • Mutation
  • Phenotype
  • Repressor Proteins / genetics*

Substances

  • Arabidopsis Proteins
  • DNA-Binding Proteins
  • RAD51B protein, Arabidopsis
  • RAD51D protein, Arabidopsis
  • Repressor Proteins
  • XRCC2 protein, Arabidopsis

Grants and funding

HS was the recipient of a PhD fellowship financed by Institut National des Sciences Biologiques (INSB/CNRS) and the Conseil régional d'Auvergne (PAVIRMA project). This work was financed by a European Union research grant (FP7-KBBE-2008-227190), the Centre National de la Recherche Scientifique, the Université Blaise Pascal, the Université d'Auvergne, and the Institut National de la Santé et de la Recherche Médicale. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.