A Rad51 presynaptic filament is sufficient to capture nucleosomal homology during recombinational repair of a DNA double-strand break.
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.
Sinha
Manisha
M
Program in Molecular Medicine, Interdisciplinary Graduate Program, University of Massachusetts Medical School, 373 Plantation Street, Worcester, MA 01605, USA.
Peterson
Craig L
CL
D001665:Binding Sites; D002843:Chromatin / Q000737:chemistry / Q000378:metabolism; D004249:DNA Damage; D004260:DNA Repair; D004271:DNA, Fungal / Q000235:genetics; D006657:Histones / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D007700:Kinetics; D009707:Nucleosomes / Q000235:genetics / Q000502:physiology*; D010446:Peptide Fragments / Q000378:metabolism; D051135:Rad51 Recombinase / Q000378:metabolism*; D011995:Recombination, Genetic; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism*
D002843:Chromatin; D004271:DNA, Fungal; D006657:Histones; D009707:Nucleosomes; D010446:Peptide Fragments; D029701:Saccharomyces cerevisiae Proteins; C495151:RAD51 protein, S cerevisiae; C495153:RAD51 protein, human; D051135:Rad51 Recombinase