Recruitment of Mec1 and Ddc1 checkpoint proteins to double-strand breaks through distinct mechanisms.
In response to DNA damage, eukaryotic cells activate checkpoint pathways that arrest cell cycle progression and induce the expression of genes required for DNA repair. In budding yeast, the homothallic switching (HO) endonuclease creates a site-specific double-strand break at the mating type (MAT) locus. Continuous HO expression results in the phosphorylation of Rad53, which is dependent on products of the ataxia telangiectasia mutated-related MEC1 gene and other checkpoint genes, including DDC1, RAD9, and RAD24. Chromatin immunoprecipitation experiments revealed that the Ddc1 protein associates with a region near the MAT locus after HO expression. Ddc1 association required Rad24 but not Mec1 or Rad9. Mec1 also associated with a region near the cleavage site after HO expression, but this association is independent of Ddc1, Rad9, and Rad24. Thus, Mec1 and Ddc1 are recruited independently to sites of DNA damage, suggesting the existence of two separate mechanisms involved in recognition of DNA damage.
Kondo
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T
Division of Biological Science, Graduate School of Science, Nagoya University, CREST, Japan Science and Technology Corporation, Chikusa-ku, Nagoya 464-0814, Japan.
Wakayama
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T
Naiki
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Matsumoto
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K
Sugimoto
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K
D002453:Cell Cycle; D018797:Cell Cycle Proteins / Q000378:metabolism; D002467:Cell Nucleus / Q000378:metabolism; D064447:Checkpoint Kinase 2; D003593:Cytoplasm / Q000378:metabolism; D004249:DNA Damage; D004260:DNA Repair; D004271:DNA, Fungal / Q000235:genetics / Q000378:metabolism*; D004268:DNA-Binding Proteins; D015252:Deoxyribonucleases, Type II Site-Specific / Q000378:metabolism; D005656:Fungal Proteins / Q000378:metabolism*; D005800:Genes, Fungal; D049770:Genes, Mating Type, Fungal; D018816:Genes, cdc; D047908:Intracellular Signaling Peptides and Proteins; D000072235:Mating Factor; D009154:Mutation; D009687:Nuclear Proteins; D010455:Peptides / Q000235:genetics; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D011995:Recombination, Genetic; D029701:Saccharomyces cerevisiae Proteins; D004718:Saccharomycetales / Q000166:cytology / Q000235:genetics / Q000378:metabolism*; D014170:Transformation, Genetic
D018797:Cell Cycle Proteins; D004271:DNA, Fungal; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; D047908:Intracellular Signaling Peptides and Proteins; D009687:Nuclear Proteins; D010455:Peptides; C501395:RAD17 protein, S cerevisiae; D011993:Recombinant Fusion Proteins; D029701:Saccharomyces cerevisiae Proteins; C069930:rad9 protein; D000072235:Mating Factor; D064447:Checkpoint Kinase 2; C088937:MEC1 protein, S cerevisiae; D017346:Protein Serine-Threonine Kinases; C067022:RAD53 protein, S cerevisiae; C530845:HO protein, S cerevisiae; C037725:SCEI protein, S cerevisiae; D015252:Deoxyribonucleases, Type II Site-Specific