title: Functional interplay between the 53BP1-ortholog Rad9 and the Mre11 complex regulates resection, end-tethering and repair of a double-strand break.
abstract: The Mre11-Rad50-Xrs2 nuclease complex, together with Sae2, initiates the 5'-to-3' resection of Double-Strand DNA Breaks (DSBs). Extended 3' single stranded DNA filaments can be exposed from a DSB through the redundant activities of the Exo1 nuclease and the Dna2 nuclease with the Sgs1 helicase. In the absence of Sae2, Mre11 binding to a DSB is prolonged, the two DNA ends cannot be kept tethered, and the DSB is not efficiently repaired. Here we show that deletion of the yeast 53BP1-ortholog RAD9 reduces Mre11 binding to a DSB, leading to Rad52 recruitment and efficient DSB end-tethering, through an Sgs1-dependent mechanism. As a consequence, deletion of RAD9 restores DSB repair either in absence of Sae2 or in presence of a nuclease defective MRX complex. We propose that, in cells lacking Sae2, Rad9/53BP1 contributes to keep Mre11 bound to a persistent DSB, protecting it from extensive DNA end resection, which may lead to potentially deleterious DNA deletions and genome rearrangements.
authors.affiliation: Department of Biosciences, University of Milan, Milano, Italy.
authors.forename: Matteo
authors.initials: M
authors.lastname: Ferrari
authors.affiliation: Department of Biosciences, University of Milan, Milano, Italy.
authors.forename: Diego
authors.initials: D
authors.lastname: Dibitetto
authors.affiliation: Department of Biosciences, University of Milan, Milano, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: De Gregorio
authors.affiliation: Department of Biology and Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, Massachusetts, United States of America.
authors.forename: Vinay V
authors.initials: VV
authors.lastname: Eapen
authors.affiliation: Department of Biosciences, University of Milan, Milano, Italy.
authors.forename: Chetan C
authors.initials: CC
authors.lastname: Rawal
authors.affiliation: Department of Biosciences, University of Milan, Milano, Italy.
authors.forename: Federico
authors.initials: F
authors.lastname: Lazzaro
authors.affiliation: Department of Biology and Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, Massachusetts, United States of America.
authors.forename: Michael
authors.initials: M
authors.lastname: Tsabar
authors.affiliation: Department of Biosciences, University of Milan, Milano, Italy.
authors.forename: Federica
authors.initials: F
authors.lastname: Marini
authors.affiliation: Department of Biology and Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, Massachusetts, United States of America.
authors.forename: James E
authors.initials: JE
authors.lastname: Haber
authors.affiliation: Department of Biosciences, University of Milan, Milano, Italy.
authors.forename: Achille
authors.initials: A
authors.lastname: Pellicioli
mesh_terms: D018797:Cell Cycle Proteins / Q000235:genetics* / Q000378:metabolism; D053903:DNA Breaks, Double-Stranded; D059766:DNA End-Joining Repair / Q000235:genetics*; D004277:DNA, Single-Stranded / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics; D004706:Endodeoxyribonucleases / Q000235:genetics* / Q000378:metabolism; D004720:Endonucleases / Q000235:genetics / Q000378:metabolism; D005090:Exodeoxyribonucleases / Q000235:genetics* / Q000378:metabolism; D059765:Homologous Recombination / Q000235:genetics*; D009154:Mutation; D051721:Rad52 DNA Repair and Recombination Protein / Q000235:genetics / Q000378:metabolism; D053484:RecQ Helicases / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics* / Q000378:metabolism
chemical_list: D018797:Cell Cycle Proteins; D004277:DNA, Single-Stranded; D004268:DNA-Binding Proteins; C497197:RAD52 protein, S cerevisiae; D051721:Rad52 DNA Repair and Recombination Protein; C107849:SAE2 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; C069930:rad9 protein; D004706:Endodeoxyribonucleases; D004720:Endonucleases; D005090:Exodeoxyribonucleases; C094191:MRE11 protein, S cerevisiae; C090472:SGS1 protein, S cerevisiae; D053484:RecQ Helicases