Dual functions of CDC6: a yeast protein required for DNA replication also inhibits nuclear division.
The Saccharomyces cerevisiae gene CDC6, whose protein product is required for DNA replication, is transcribed only in late G1 and S phases. We have discovered a critical reason why CDC6 expression is regulated in this fashion. Constitutive CDC6 transcription greatly delayed the initiation of M phase without effecting the G1-S transition or growth rate. This occurred in both fission and budding yeasts. The CDC6-induced M phase delay was dependent on the wee1/mik1 mitotic inhibitor kinases and was greatly accentuated in strains defective for the cdc25/MIH1 mitotic inducer phosphatases, indicating that CDC6 indirectly inhibits activation of the p34cdc2/CDC28 M phase kinase. Thus CDC6 appears to have an important and perhaps unique dual role in S phase, it is first required for the initiation of DNA replication and then actively participates in the suppression of nuclear division.
Bueno
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A
Department of Molecular and Cell Biology, Scripps Research Institute, La Jolla, CA 92037.
Russell
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P
D001483:Base Sequence; D002453:Cell Cycle / Q000187:drug effects / Q000235:genetics*; D018797:Cell Cycle Proteins; D002455:Cell Division; D002467:Cell Nucleus / Q000502:physiology* / Q000648:ultrastructure; D004261:DNA Replication / Q000235:genetics*; D005656:Fungal Proteins / Q000235:genetics* / Q000378:metabolism*; D005800:Genes, Fungal; D000072235:Mating Factor; D008938:Mitosis / Q000235:genetics; D008969:Molecular Sequence Data; D009838:Oligodeoxyribonucleotides; D010455:Peptides / Q000494:pharmacology; D010675:Pheromones / Q000494:pharmacology; D010957:Plasmids; D017027:Protein Tyrosine Phosphatases / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000235:genetics* / Q000502:physiology; D029701:Saccharomyces cerevisiae Proteins; D014158:Transcription, Genetic; D020666:ras-GRF1
C066503:CDC6 protein, S cerevisiae; D018797:Cell Cycle Proteins; D005656:Fungal Proteins; D009838:Oligodeoxyribonucleotides; D010455:Peptides; D010675:Pheromones; D029701:Saccharomyces cerevisiae Proteins; D020666:ras-GRF1; D000072235:Mating Factor; D017027:Protein Tyrosine Phosphatases