title: mik1(+) G1-S transcription regulates mitotic entry in fission yeast.
abstract: In the fission yeast Schizosaccharomyces pombe Mik1p, in combination with Wee1p, is an important inhibitor of mitosis through direct phosphorylation of Cdc2p. Here we present the observation that mik1(+) is transcribed during G1- and S-phase in normally dividing cells. mik1(+) transcription is regulated by the MCB-DSC1 system, which controls expression of other genes at the G1-S interval. mik1(+) is shown to be an important target of MCB-DSC1 as it is epistatic for the mitotic delay phenotype displayed in cdc10-C4 cells, which are mutated in a component of DSC1. The mitotic delay in cdc10-C4 cells is bypassed by cdc2-1w, suggesting that mik1(+) acts directly on cdc2(+), with no checkpoint function involved. Thus, mik1(+) represents a new type of MCB-DSC1 regulated gene in fission yeast, whose gene product is exclusively expressed during G1- and S-phase to prevent premature mitosis during this cell cycle stage.
authors.affiliation: Division of Biochemistry and Molecular Biology, Institute of Biological and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK.
authors.forename: S S
authors.initials: SS
authors.lastname: Ng
authors.forename: M
authors.initials: M
authors.lastname: Anderson
authors.forename: S
authors.initials: S
authors.lastname: White
authors.forename: C J
authors.initials: CJ
authors.lastname: McInerny
mesh_terms: D001483:Base Sequence; D016203:CDC2 Protein Kinase / Q000378:metabolism; D017931:DNA Primers / Q000235:genetics; D004271:DNA, Fungal / Q000235:genetics / Q000378:metabolism; D016193:G1 Phase / Q000235:genetics; D015966:Gene Expression Regulation, Fungal; D005800:Genes, Fungal; D008938:Mitosis / Q000235:genetics*; D008969:Molecular Sequence Data; D010641:Phenotype; D011401:Promoter Regions, Genetic; D016196:S Phase / Q000235:genetics; D012568:Schizosaccharomyces / Q000166:cytology* / Q000235:genetics* / Q000378:metabolism; D014158:Transcription, Genetic
chemical_list: D017931:DNA Primers; D004271:DNA, Fungal; D016203:CDC2 Protein Kinase