title: EXO1-dependent single-stranded DNA at telomeres activates subsets of DNA damage and spindle checkpoint pathways in budding yeast yku70Delta mutants.
abstract: We have examined the role of checkpoint pathways in responding to a yku70Delta defect in budding yeast. We show that CHK1, MEC1, and RAD9 checkpoint genes are required for efficient cell cycle arrest of yku70Delta mutants cultured at 37 degrees C, whereas RAD17, RAD24, MEC3, DDC1, and DUN1 play insignificant roles. We establish that cell cycle arrest of yku70Delta mutants is associated with increasing levels of single-stranded DNA in subtelomeric Y' regions, and find that the mismatch repair-associated EXO1 gene is required for both ssDNA generation and cell cycle arrest of yku70Delta mutants. In contrast, MRE11 is not required for ssDNA generation. The behavior of yku70Delta exo1Delta double mutants strongly indicates that ssDNA is an important component of the arrest signal in yku70Delta mutants and demonstrates a link between damaged telomeres and mismatch repair-associated exonucleases. This link is confirmed by our demonstration that EXO1 also plays a role in ssDNA generation in cdc13-1 mutants. We have also found that the MAD2 but not the BUB2 spindle checkpoint gene is required for efficient arrest of yku70Delta mutants. Therefore, subsets of both DNA-damage and spindle checkpoint pathways cooperate to regulate cell division of yku70Delta mutants.
authors.affiliation: School of Biological Sciences, University of Manchester, Manchester M13 9PT, UK.
authors.forename: Laura
authors.initials: L
authors.lastname: Maringele
authors.forename: David
authors.initials: D
authors.lastname: Lydall
mesh_terms: D034961:Antigens, Nuclear; D020137:Base Pair Mismatch; D002135:Calcium-Binding Proteins / Q000502:physiology; D002352:Carrier Proteins; D002453:Cell Cycle / Q000235:genetics / Q000502:physiology*; D018797:Cell Cycle Proteins / Q000502:physiology; D000071877:Checkpoint Kinase 1; D004249:DNA Damage; D004265:DNA Helicases; D004260:DNA Repair; D004271:DNA, Fungal / Q000235:genetics*; D004277:DNA, Single-Stranded / Q000235:genetics* / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D019281:Dimerization; D005090:Exodeoxyribonucleases / Q000502:physiology*; D005656:Fungal Proteins / Q000502:physiology; D018816:Genes, cdc; D047908:Intracellular Signaling Peptides and Proteins; D000072200:Ku Autoantigen; D064246:Mad2 Proteins; D009687:Nuclear Proteins / Q000737:chemistry / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D011494:Protein Kinases / Q000502:physiology; D017346:Protein Serine-Threonine Kinases; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D017384:Sequence Deletion; D016615:Telomere / Q000378:metabolism*
chemical_list: D034961:Antigens, Nuclear; D002135:Calcium-Binding Proteins; D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D004271:DNA, Fungal; D004277:DNA, Single-Stranded; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; D047908:Intracellular Signaling Peptides and Proteins; C577695:MAD2 protein, S cerevisiae; D064246:Mad2 Proteins; D009687:Nuclear Proteins; D029701:Saccharomyces cerevisiae Proteins; C081647:high affinity DNA-binding factor, S cerevisiae; C069930:rad9 protein; D011494:Protein Kinases; C000605867:CHEK1 protein, human; D000071877:Checkpoint Kinase 1; C088937:MEC1 protein, S cerevisiae; D017346:Protein Serine-Threonine Kinases; D005090:Exodeoxyribonucleases; C028450:exodeoxyribonuclease I; D004265:DNA Helicases; C106893:XRCC5 protein, human; C000606509:Xrcc6 protein, human; D000072200:Ku Autoantigen