Initiation of meiosis and sporulation in Saccharomyces cerevisiae requires a novel protein kinase homologue.
SME1 was cloned due to its high copy number effect: it enabled MATa/MAT alpha diploid cells to undergo meiosis and sporulation in a vegetative medium. Disruption of SME1 resulted in a recessive Spo- phenotype. These results suggest that SME1 is a positive regulator for meiosis. DNA sequencing analysis revealed an open reading frame of 645 amino acids. An amino terminal peptide of ca 400 amino acids in the deduced protein was similar to known protein kinases. Transcription of SME1 was regulated negatively by nitrogen and glucose and positively by MATa/MAT alpha and IME1, another positive regulator gene of meiosis. By complementation analysis, SME1 was found to be identical to IME2, which had been shown to be important in meiosis. These results suggest that IME1 product stimulates meiosis by activating transcription of SME1 (IME2) and that protein phosphorylation is required for initiation of meiosis.
Center for Gene Science, Hiroshima University, Higashi-Hiroshima, Japan.
M
M
Yoshida
H
H
Kawaguchi
Y
Y
Sakata
K
K
Kominami
M
M
Hirano
H
H
Shima
R
R
Akada
I
I
Yamashita
D000595:Amino Acid Sequence; D001483:Base Sequence; D018797:Cell Cycle Proteins; D003001:Cloning, Molecular; D005656:Fungal Proteins / Q000235:genetics* / Q000378:metabolism; D015966:Gene Expression Regulation, Fungal; D005800:Genes, Fungal; D047908:Intracellular Signaling Peptides and Proteins; D008540:Meiosis; D008969:Molecular Sequence Data; D011494:Protein Kinases / Q000235:genetics* / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases; D015183:Restriction Mapping; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000502:physiology; D029701:Saccharomyces cerevisiae Proteins; D012689:Sequence Homology, Nucleic Acid; D013172:Spores, Fungal; D014158:Transcription, Genetic
D018797:Cell Cycle Proteins; D005656:Fungal Proteins; D047908:Intracellular Signaling Peptides and Proteins; D029701:Saccharomyces cerevisiae Proteins; D011494:Protein Kinases; C064979:IME2 protein, S cerevisiae; D017346:Protein Serine-Threonine Kinases