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Single-Molecule Imaging Reveals How Mre11-Rad50-Nbs1 Initiates DNA Break Repair.
Myler, Logan R; Gallardo, Ignacio F; Soniat, Michael M; Deshpande, Rajashree A; Gonzalez, Xenia B; Kim, Yoori; Paull, Tanya T; Finkelstein, Ilya J.
Afiliação
  • Myler LR; Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712, USA; Howard Hughes Medical Institute, The University of Texas at Austin, Austin, TX 78712, USA; Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, TX 78712, USA.
  • Gallardo IF; Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712, USA; Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, TX 78712, USA.
  • Soniat MM; Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712, USA; Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, TX 78712, USA.
  • Deshpande RA; Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712, USA; Howard Hughes Medical Institute, The University of Texas at Austin, Austin, TX 78712, USA.
  • Gonzalez XB; Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712, USA; Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, TX 78712, USA.
  • Kim Y; Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712, USA; Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, TX 78712, USA.
  • Paull TT; Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712, USA; Howard Hughes Medical Institute, The University of Texas at Austin, Austin, TX 78712, USA.
  • Finkelstein IJ; Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712, USA; Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, TX 78712, USA. Electronic address: ifinkelstein@cm.utexas.edu.
Mol Cell ; 67(5): 891-898.e4, 2017 Sep 07.
Article em En | MEDLINE | ID: mdl-28867292
ABSTRACT
DNA double-strand break (DSB) repair is essential for maintaining our genomes. Mre11-Rad50-Nbs1 (MRN) and Ku70-Ku80 (Ku) direct distinct DSB repair pathways, but the interplay between these complexes at a DSB remains unclear. Here, we use high-throughput single-molecule microscopy to show that MRN searches for free DNA ends by one-dimensional facilitated diffusion, even on nucleosome-coated DNA. Rad50 binds homoduplex DNA and promotes facilitated diffusion, whereas Mre11 is required for DNA end recognition and nuclease activities. MRN gains access to occluded DNA ends by removing Ku or other DNA adducts via an Mre11-dependent nucleolytic reaction. Next, MRN loads exonuclease 1 (Exo1) onto the free DNA ends to initiate DNA resection. In the presence of replication protein A (RPA), MRN acts as a processivity factor for Exo1, retaining the exonuclease on DNA for long-range resection. Our results provide a mechanism for how MRN promotes homologous recombination on nucleosome-coated DNA.
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Texto completo: 1 Base de dados: MEDLINE Assunto principal: Proteínas Nucleares / Nucleossomos / Proteínas de Ciclo Celular / Enzimas Reparadoras do DNA / Proteínas de Ligação a DNA / Quebras de DNA de Cadeia Dupla / Reparo de DNA por Recombinação / Imagem Individual de Molécula Limite: Humans Idioma: En Ano de publicação: 2017 Tipo de documento: Article
Texto completo
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Texto completo: 1 Base de dados: MEDLINE Assunto principal: Proteínas Nucleares / Nucleossomos / Proteínas de Ciclo Celular / Enzimas Reparadoras do DNA / Proteínas de Ligação a DNA / Quebras de DNA de Cadeia Dupla / Reparo de DNA por Recombinação / Imagem Individual de Molécula Limite: Humans Idioma: En Ano de publicação: 2017 Tipo de documento: Article