title: Control of the yeast telomeric senescence survival pathways of recombination by the Mec1 and Mec3 DNA damage sensors and RPA.
abstract: Saccharomyces cerevisiae telomerase-negative cells undergo homologous recombination on subtelomeric or TG(1-3) telomeric sequences, thus allowing Type I or Type II post-senescence survival, respectively. Here, we find that the DNA damage sensors, Mec1, Mec3 and Rad24 control Type II recombination, while the Rad9 adaptor protein and the Rad53 and Chk1 effector kinases have no effect on survivor type selection. Therefore, the Mec1 and Mec3 checkpoint complexes control telomeric recombination independently of their roles in generating and amplifying the Mec1-Rad53-Chk1 kinase cascade. rfa1-t11 mutant cells, bearing a mutation in Replication Protein A (RPA) conferring a defect in recruiting Mec1-Ddc2, were also deficient in both types of telomeric recombination. Importantly, expression of an Rfa1-t11-Ddc2 hybrid fusion protein restored checkpoint-dependent arrest, but did not rescue defective telomeric recombination. Therefore, the Rfa1-t11-associated defect in telomeric recombination is not solely due to its failure to recruit Mec1. We have also isolated novel alleles of RFA1 that were deficient in Type I but not in Type II recombination and proficient in checkpoint control. Therefore, the checkpoint and recombination functions of RPA can be genetically separated, as can the RPA-mediated control of the two types of telomeric recombination.
authors.affiliation: UMR CNRS no. 5161, Ecole Normale Supérieure de Lyon, IFR128 BioSciences Gerland, 69364 Lyon, France.
authors.forename: Nathalie
authors.initials: N
authors.lastname: Grandin
authors.forename: Michel
authors.initials: M
authors.lastname: Charbonneau
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D001665:Binding Sites; D018797:Cell Cycle Proteins / Q000235:genetics / Q000502:physiology*; D019926:Cyclin B / Q000378:metabolism; D004249:DNA Damage; D004268:DNA-Binding Proteins / Q000235:genetics / Q000502:physiology*; D017353:Gene Deletion; D047908:Intracellular Signaling Peptides and Proteins; D009154:Mutation; D010750:Phosphoproteins / Q000235:genetics; D017346:Protein Serine-Threonine Kinases; D012313:RNA / Q000235:genetics; D051721:Rad52 DNA Repair and Recombination Protein / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D011995:Recombination, Genetic; D051716:Replication Protein A / Q000235:genetics / Q000502:physiology; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D019098:Telomerase / Q000235:genetics; D016615:Telomere / Q000737:chemistry*; D034501:Telomere-Binding Proteins / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000502:physiology*
chemical_list: D048868:Adaptor Proteins, Signal Transducing; C093749:CLB2 protein, S cerevisiae; C452219:Cdc13 protein, S cerevisiae; D018797:Cell Cycle Proteins; D019926:Cyclin B; D004268:DNA-Binding Proteins; D047908:Intracellular Signaling Peptides and Proteins; C440014:LCD1 protein, S cerevisiae; C099938:MEC3 protein, S cerevisiae; D010750:Phosphoproteins; C497197:RAD52 protein, S cerevisiae; C082728:RFA1 protein, S cerevisiae; D051721:Rad52 DNA Repair and Recombination Protein; D011993:Recombinant Fusion Proteins; D051716:Replication Protein A; D029701:Saccharomyces cerevisiae Proteins; D034501:Telomere-Binding Proteins; D014157:Transcription Factors; C422952:telomerase RNA; D012313:RNA; C088937:MEC1 protein, S cerevisiae; D017346:Protein Serine-Threonine Kinases; D019098:Telomerase