The yeast MCK1 gene encodes a protein kinase homolog that activates early meiotic gene expression.
We have identified a yeast gene, MCK1, that encodes a positive regulator of meiosis and spore formation. Sequence analysis revealed that MCK1 encodes a protein kinase homolog identical to YPK1, a phosphotyrosyl protein with demonstrated protein kinase activity. Increased MCK1 gene dosage accelerates the sporulation program; mck1 mutations cause delayed and decreased levels of sporulation. MCK1 is required during sporulation for maximal transcript accumulation from IME1, which encodes a meiotic activator. MCK1 is required in vegetative cells for basal IME1 expression, as evidenced by functional assays of an ime1-HIS3 fusion gene. MCK1 is also required for efficient ascus maturation. Although expression of IME1 from the GAL1 promoter restored high-level sporulation to mck1 mutants, it did not correct the ascus-maturation defect. This observation indicates that MCK1 is required, independently, for both the activation of IME1 and subsequent ascus maturation. Expression of an mck1-lacZ fusion gene was not regulated by the signals that govern meiosis. This observation is consistent with evidence that MCK1 plays a role in governing centromere function during vegetative growth as well as sporulation.
Neigeborn
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Institute of Cancer Research, Columbia University, New York, New York 10032.
Mitchell
A P
AP
D000595:Amino Acid Sequence; D001483:Base Sequence; D015966:Gene Expression Regulation, Fungal; D005800:Genes, Fungal; D005809:Genes, Regulator; D038362:Glycogen Synthase Kinase 3; D007700:Kinetics; D008540:Meiosis; D008969:Molecular Sequence Data; D010957:Plasmids; D011494:Protein Kinases / Q000235:genetics*; D011505:Protein-Tyrosine Kinases / Q000235:genetics*; D015183:Restriction Mapping; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000235:genetics* / Q000502:physiology; D029701:Saccharomyces cerevisiae Proteins; D012689:Sequence Homology, Nucleic Acid; D013172:Spores, Fungal / Q000502:physiology
D029701:Saccharomyces cerevisiae Proteins; D011494:Protein Kinases; D011505:Protein-Tyrosine Kinases; D038362:Glycogen Synthase Kinase 3; C068124:MCK1 protein, S cerevisiae