title: RPA Stabilization of Single-Stranded DNA Is Critical for Break-Induced Replication.
abstract: DNA double-strand breaks (DSBs) are cytotoxic lesions that must be accurately repaired to maintain genome stability. Replication protein A (RPA) plays an important role in homology-dependent repair of DSBs by protecting the single-stranded DNA (ssDNA) intermediates formed by end resection and by facilitating Rad51 loading. We found that hypomorphic mutants of RFA1 that support intra-chromosomal homologous recombination are profoundly defective for repair processes involving long tracts of DNA synthesis, in particular break-induced replication (BIR). The BIR defects of the rfa1 mutants could be partially suppressed by eliminating the Sgs1-Dna2 resection pathway, suggesting that Dna2 nuclease attacks the ssDNA formed during end resection when not fully protected by RPA. Overexpression of Rad51 was also found to suppress the rfa1 BIR defects. We suggest that Rad51 binding to the ssDNA formed by excessive end resection and during D-loop migration can partially compensate for dysfunctional RPA.
authors.affiliation: Department of Microbiology and Immunology, Columbia University Medical Center, New York, NY 10032, USA.
authors.forename: Patrick
authors.initials: P
authors.lastname: Ruff
authors.affiliation: Department of Microbiology and Immunology, Columbia University Medical Center, New York, NY 10032, USA.
authors.forename: Roberto A
authors.initials: RA
authors.lastname: Donnianni
authors.affiliation: Department of Microbiology and Immunology, Columbia University Medical Center, New York, NY 10032, USA.
authors.forename: Eleanor
authors.initials: E
authors.lastname: Glancy
authors.affiliation: Department of Microbiology and Immunology, Columbia University Medical Center, New York, NY 10032, USA.
authors.forename: Julyun
authors.initials: J
authors.lastname: Oh
authors.affiliation: Department of Microbiology and Immunology, Columbia University Medical Center, New York, NY 10032, USA. Electronic address: lss5@cumc.columbia.edu.
authors.forename: Lorraine S
authors.initials: LS
authors.lastname: Symington
mesh_terms: D053903:DNA Breaks, Double-Stranded; D004249:DNA Damage / Q000235:genetics; D004265:DNA Helicases / Q000235:genetics; D004260:DNA Repair / Q000235:genetics; D004261:DNA Replication / Q000235:genetics*; D004277:DNA, Single-Stranded; D004268:DNA-Binding Proteins / Q000235:genetics; D042822:Genomic Instability / Q000235:genetics; D059765:Homologous Recombination / Q000235:genetics*; D051135:Rad51 Recombinase / Q000235:genetics*; D053484:RecQ Helicases / Q000235:genetics; D051716:Replication Protein A / Q000235:genetics*; D012441:Saccharomyces cerevisiae / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics
chemical_list: D004277:DNA, Single-Stranded; D004268:DNA-Binding Proteins; D051716:Replication Protein A; D029701:Saccharomyces cerevisiae Proteins; D051135:Rad51 Recombinase; C090472:SGS1 protein, S cerevisiae; D004265:DNA Helicases; C410222:DNA2 protein, S cerevisiae; D053484:RecQ Helicases
keywords: DSB repair; Dna2; RPA; Rad51; break-induced replication; homologous recombination