Ultrafine anaphase bridges, broken DNA and illegitimate recombination induced by a replication fork barrier

Nucleic Acids Res. 2011 Aug;39(15):6568-84. doi: 10.1093/nar/gkr340. Epub 2011 May 16.

Abstract

Most DNA double-strand breaks (DSBs) in S- and G2-phase cells are repaired accurately by Rad51-dependent sister chromatid recombination. However, a minority give rise to gross chromosome rearrangements (GCRs), which can result in disease/death. What determines whether a DSB is repaired accurately or inaccurately is currently unclear. We provide evidence that suggests that perturbing replication by a non-programmed protein-DNA replication fork barrier results in the persistence of replication intermediates (most likely regions of unreplicated DNA) into mitosis, which results in anaphase bridge formation and ultimately to DNA breakage. However, unlike previously characterised replication-associated DSBs, these breaks are repaired mainly by Rad51-independent processes such as single-strand annealing, and are therefore prone to generate GCRs. These data highlight how a replication-associated DSB can be predisposed to give rise to genome rearrangements in eukaryotes.

Publication types

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

MeSH terms

  • Anaphase / genetics
  • Chromosome Deletion
  • DNA / ultrastructure
  • DNA Breaks, Double-Stranded*
  • DNA Helicases / metabolism
  • DNA Replication*
  • Epstein-Barr Virus Nuclear Antigens / metabolism
  • Lac Repressors / metabolism
  • Mitosis
  • Mutation
  • Operator Regions, Genetic
  • Recombination, Genetic*
  • Schizosaccharomyces / genetics
  • Schizosaccharomyces pombe Proteins / metabolism

Substances

  • Epstein-Barr Virus Nuclear Antigens
  • Lac Repressors
  • Schizosaccharomyces pombe Proteins
  • DNA
  • DNA Helicases
  • Pfh1 protein, S pombe
  • EBV-encoded nuclear antigen 1