A Rad51 presynaptic filament is sufficient to capture nucleosomal homology during recombinational repair of a DNA double-strand break

Mol Cell. 2008 Jun 20;30(6):803-10. doi: 10.1016/j.molcel.2008.04.015.

Abstract

Repair of chromosomal DNA double-strand breaks by homologous recombination is essential for cell survival and genome stability. Within eukaryotic cells, this repair pathway requires a search for a homologous donor sequence and a subsequent strand invasion event on chromatin fibers. We employ a biotin-streptavidin minichromosome capture assay to show that yRad51 or hRad51 presynaptic filaments are sufficient to locate a homologous sequence and form initial joints, even on the surface of a nucleosome. Furthermore, we present evidence that the Rad54 chromatin-remodeling enzyme functions to convert these initial metastable products of the homology search to a stable joint molecule that is competent for subsequent steps of the repair process. Thus, contrary to popular belief, nucleosomes do not pose a potent barrier for successful recognition and capture of homology by an invading presynaptic filament.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Binding Sites
  • Chromatin / chemistry
  • Chromatin / metabolism
  • DNA Damage*
  • DNA Repair*
  • DNA, Fungal / genetics
  • Histones / chemistry
  • Histones / metabolism
  • Humans
  • Kinetics
  • Nucleosomes / genetics
  • Nucleosomes / physiology*
  • Peptide Fragments / metabolism
  • Rad51 Recombinase / metabolism*
  • Recombination, Genetic*
  • Saccharomyces cerevisiae / enzymology
  • Saccharomyces cerevisiae / genetics
  • Saccharomyces cerevisiae Proteins / metabolism*

Substances

  • Chromatin
  • DNA, Fungal
  • Histones
  • Nucleosomes
  • Peptide Fragments
  • Saccharomyces cerevisiae Proteins
  • RAD51 protein, S cerevisiae
  • RAD51 protein, human
  • Rad51 Recombinase