Different genetic requirements for repair of replication-born double-strand breaks by sister-chromatid recombination and break-induced replication

Nucleic Acids Res. 2007;35(19):6560-70. doi: 10.1093/nar/gkm488. Epub 2007 Sep 28.

Abstract

Homologous recombination (HR) is the major mechanism used to repair double-strand breaks (DSBs) that result from replication, but a study of repair of DSBs specifically induced during S-phase is lacking. Using an inverted-repeat assay in which a DSB is generated by the encountering of the replication fork with nicks, we can physically detect repair by sister-chromatid recombination (SCR) and intra-chromatid break-induced replication (IC-BIR). As expected, both events depend on Rad52, but, in contrast to previous data, both require Rad59, suggesting a prominent role of Rad59 in repair of replication-born DSBs. In the absence of Rad51, SCR is severely affected while IC-BIR increases, a phenotype that is also observed in the absence of Rad54 but not of its paralog Rdh54/Tid1. These data are consistent with SCR occurring by Rad51-dependent mechanisms assisted by Rad54, and indicate that in the absence of strand exchange-dependent SCR, breaks can be channeled to IC-BIR, which works efficiently in the absence of Rad51. Our study provides molecular evidence for inversions between repeats occurring by BIR followed by single-strand annealing (SSA) in the absence of strand exchange.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Chromatids / genetics*
  • DNA Breaks, Double-Stranded*
  • DNA Helicases
  • DNA Repair Enzymes
  • DNA Repair*
  • DNA Replication*
  • DNA Topoisomerases
  • DNA-Binding Proteins / physiology
  • Rad51 Recombinase / metabolism
  • Recombination, Genetic*
  • Saccharomyces cerevisiae / genetics*
  • Saccharomyces cerevisiae / metabolism
  • Saccharomyces cerevisiae Proteins / metabolism
  • Saccharomyces cerevisiae Proteins / physiology
  • Sister Chromatid Exchange

Substances

  • DNA-Binding Proteins
  • RAD59 protein, S cerevisiae
  • Saccharomyces cerevisiae Proteins
  • RAD51 protein, S cerevisiae
  • Rad51 Recombinase
  • RAD54 protein, S cerevisiae
  • DNA Helicases
  • DNA Topoisomerases
  • RDH54 protein, S cerevisiae
  • DNA Repair Enzymes