Novel WD-repeat protein Mip1p facilitates function of the meiotic regulator Mei2p in fission yeast.
In fission yeast, the onset of meiosis is triggered by activation of the RNA-binding protein Mei2p. We screened for a high-copy-number suppressor of the ectopic meiosis induced by expression of an active form of Mei2p. Consequently we isolated a truncated form of a novel gene, named mip1, from a fission yeast genomic library. The mip1 gene encoded a protein of 1,313 amino acids which carried a WD-repeat motif in the C-terminal region and was apparently conserved among eukaryotes. Mip1p was cytoplasmic, and two-hybrid and immunoprecipitation analyses demonstrated that Mip1p was bound to Mei2p in vivo. Genetic evidence indicated that wild-type Mip1p was required for the function of Mei2p to induce meiosis and that the truncated form of it (Mip1-15p) dominantly interfered with Mei2p. Mip1p appeared to be involved also in conjugation, associating with Ste11p, which is a key transcription factor for sexual development. Furthermore, Mip1p was essential for cell growth, to which neither Mei2p nor Ste11p is relevant. These results suggest that Mip1p assists functional expression of a number of proteins required for proliferation and sexual development in fission yeast.
Shinozaki-Yabana
S
S
Department of Biophysics and Biochemistry, Graduate School of Science, University of Tokyo, Hongo, Tokyo 113-0033, Japan.
Watanabe
Y
Y
Yamamoto
M
M
D000483:Alleles; D001483:Base Sequence; D002455:Cell Division / Q000235:genetics / Q000502:physiology; D003227:Conjugation, Genetic; D003593:Cytoplasm / Q000378:metabolism; D017931:DNA Primers / Q000235:genetics; D005656:Fungal Proteins / Q000235:genetics / Q000502:physiology*; D005800:Genes, Fungal; D008540:Meiosis / Q000235:genetics / Q000502:physiology*; D008969:Molecular Sequence Data; D016601:RNA-Binding Proteins / Q000235:genetics / Q000502:physiology*; D012568:Schizosaccharomyces / Q000166:cytology / Q000235:genetics / Q000378:metabolism*; D029702:Schizosaccharomyces pombe Proteins; D013489:Suppression, Genetic; D014157:Transcription Factors / Q000235:genetics / Q000502:physiology
D017931:DNA Primers; D005656:Fungal Proteins; D016601:RNA-Binding Proteins; D029702:Schizosaccharomyces pombe Proteins; D014157:Transcription Factors; C088896:mei2 protein, S pombe; C071596:ste11 protein, S pombe