Characterization of Schizosaccharomyces pombe mcm7(+) and cdc23(+) (MCM10) and interactions with replication checkpoints.
MCM proteins are required for the proper regulation of DNA replication. We cloned fission yeast mcm7(+) and showed it is essential for viability; spores lacking mcm7(+) begin S phase later than wild-type cells and arrest with an apparent 2C DNA content. We isolated a novel temperature-sensitive allele, mcm7-98, and also characterized two temperature-sensitive alleles of the fission yeast homolog of MCM10, cdc23(+). mcm7-98 and both cdc23ts alleles arrest with damaged chromosomes and an S phase delay. We find that mcm7-98 is synthetically lethal with the other mcmts mutants but does not interact genetically with either cdc23ts allele. However, cdc23-M36 interacts with mcm4ts. Unlike other mcm mutants or cdc23, mcm7-98 is synthetically lethal with checkpoint mutants Deltacds1, Deltachk1, or Deltarad3, suggesting chromosomal defects even at permissive temperature. Mcm7p is a nuclear protein throughout the cell cycle, and its localization is dependent on the other MCM proteins. Our data suggest that the Mcm3p-Mcm5p dimer interacts with the Mcm4p-Mcm6p-Mcm7p core complex through Mcm7p.
Liang
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DT
Department of Biology, University of California, San Diego, 92093, USA.
Forsburg
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SL
D000483:Alleles; D064173:Anaphase-Promoting Complex-Cyclosome; D064196:Apc8 Subunit, Anaphase-Promoting Complex-Cyclosome; D001483:Base Sequence; D018797:Cell Cycle Proteins / Q000235:genetics* / Q000502:physiology; D003001:Cloning, Molecular; D017931:DNA Primers; D004261:DNA Replication / Q000235:genetics*; D019084:Fluorescent Antibody Technique, Indirect; D010448:Peptide Initiation Factors / Q000235:genetics* / Q000502:physiology; D010641:Phenotype; D016196:S Phase; D029701:Saccharomyces cerevisiae Proteins; D012568:Schizosaccharomyces / Q000235:genetics*; D013696:Temperature; D043743:Ubiquitin-Protein Ligase Complexes
D064196:Apc8 Subunit, Anaphase-Promoting Complex-Cyclosome; C577441:CDC23 protein, S cerevisiae; D018797:Cell Cycle Proteins; D017931:DNA Primers; D010448:Peptide Initiation Factors; D029701:Saccharomyces cerevisiae Proteins; D043743:Ubiquitin-Protein Ligase Complexes; D064173:Anaphase-Promoting Complex-Cyclosome