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.
Program in Molecular Medicine, Interdisciplinary Graduate Program, University of Massachusetts Medical School, 373 Plantation Street, Worcester, MA 01605, USA.
Manisha
M
Sinha
Craig L
CL
Peterson
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