The ERCC1/XPF endonuclease is required for completion of homologous recombination at DNA replication forks stalled by inter-strand cross-links

Nucleic Acids Res. 2009 Oct;37(19):6400-13. doi: 10.1093/nar/gkp705. Epub 2009 Aug 27.

Abstract

Both the ERCC1-XPF complex and the proteins involved in homoIogous recombination (HR) have critical roles in inter-strand cross-link (ICL) repair. Here, we report that mitomycin C-induced lesions inhibit replication fork elongation. Furthermore, mitomycin C-induced DNA double-strand breaks (DSBs) are the result of the collapse of ICL-stalled replication forks. These are not formed through replication run off, as we show that mitomycin C or cisplatin-induced DNA lesions are not incised by global genome nucleotide excision repair (GGR). We also suggest that ICL-lesion repair is initiated either by replication or transcription, as the GGR does not incise ICL-lesions. Furthermore, we report that RAD51 foci are induced by cisplatin or mitomycin C independently of ERCC1, but that mitomycin C-induced HR measured in a reporter construct is impaired in ERCC1-defective cells. These data suggest that ERCC1-XPF plays a role in completion of HR in ICL repair. We also find no additional sensitivity to cisplatin by siRNA co-depletion of XRCC3 and ERCC1, showing that the two proteins act on the same pathway to promote survival.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Line
  • Cisplatin / toxicity
  • Cricetinae
  • Cross-Linking Reagents / toxicity*
  • DNA Breaks, Double-Stranded
  • DNA Repair*
  • DNA Replication / drug effects
  • DNA-Binding Proteins / metabolism*
  • Endonucleases / metabolism*
  • Humans
  • Mitomycin / toxicity
  • Mutation
  • Rad51 Recombinase / genetics
  • Recombination, Genetic*

Substances

  • Cross-Linking Reagents
  • DNA-Binding Proteins
  • xeroderma pigmentosum group F protein
  • Mitomycin
  • Rad51 Recombinase
  • ERCC1 protein, human
  • Endonucleases
  • Cisplatin