title: Mei4p coordinates the onset of meiosis I by regulating cdc25+ in fission yeast.
abstract: The kinase Cdc2p is a central regulator of entry into and progression through nuclear division during mitosis and meiosis in eukaryotes. Cdc2p is activated at the onset of mitosis by dephosphorylation on tyrosine-15, the phosphorylation status of which is determined mainly by the kinase Wee1p and the phosphatase Cdc25p. In fission yeast, the forkhead-type transcription factor Mei4p is required for expression of many genes during meiosis, with mei4 mutant cells arresting before meiosis I. The mechanism of cell cycle arrest in mei4 cells has remained unknown, however. We now show that cdc25(+) is an important target of Mei4p in control of entry into meiosis I. Forced dephosphorylation of Cdc2p on tyrosine-15 thus induced meiosis I in mei4 mutant cells without a delay, although no spores were formed. We propose that Mei4p acts as a rate-limiting regulator of meiosis I by activating cdc25(+) transcription in coordination with other meiotic events.
authors.affiliation: Department of Biochemistry and Cell Biology, Graduate School of Medicine, Nagoya City University, 1 Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya 467-8601, Japan.
authors.forename: Yuko
authors.initials: Y
authors.lastname: Murakami-Tonami
authors.forename: Chisato
authors.initials: C
authors.lastname: Yamada-Namikawa
authors.forename: Akiko
authors.initials: A
authors.lastname: Tochigi
authors.forename: Norio
authors.initials: N
authors.lastname: Hasegawa
authors.forename: Hisae
authors.initials: H
authors.lastname: Kojima
authors.forename: Mitoshi
authors.initials: M
authors.lastname: Kunimatsu
authors.forename: Makoto
authors.initials: M
authors.lastname: Nakanishi
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Murakami
mesh_terms: D018797:Cell Cycle Proteins / Q000235:genetics* / Q000378:metabolism*; D047369:Chromatin Immunoprecipitation; D005656:Fungal Proteins / Q000235:genetics* / Q000378:metabolism*; D017353:Gene Deletion; D015966:Gene Expression Regulation, Fungal; D008540:Meiosis / Q000235:genetics*; D012568:Schizosaccharomyces / Q000235:genetics*; D029702:Schizosaccharomyces pombe Proteins / Q000235:genetics / Q000378:metabolism*; D020666:ras-GRF1 / Q000235:genetics* / Q000378:metabolism*