title: A mutation in SPC42, which encodes a component of the spindle pole body, results in production of two-spored asci in Saccharomyces cerevisiae.
abstract: In the yeast Saccharomyces cerevisiae, SPC42 is an essential gene, which encodes one of the major components of the spindle pole body (SPB). We report on a mutation in the SPC42 gene (spc42-102) that results in a sporulation-specific defect. Mitotic growth of haploid and diploid spc42-102 strains is normal and both exhibit the same growth rates as the isogenic wild-type strains. Many diploid spc42-102/spc42-102 cells undergo normal meiotic nuclear divisions, producing four haploid nuclei. However, a significant fraction of meiotic spc42-102/spc42-102 cells contain two immature SPBs and aberrant nuclei that are not surrounded by a prospore membrane. Some 40% of the resultant asci contain only two spores, while wild-type diploid cells almost always produce four-spored asci. Segregation of auxotrophic markers that are tightly linked to the centromere reveals that two-spore asci formed from spc42-102/spc42-102 diploid cells exclusively contain nonsister haploid spores. Western analysis and measurements of the fluorescent signal from an Spc42p-GFP (green fluorescent protein) fusion reveal that the mutant strain fails to accumulate Spc42p at meiosis. Thus, our results suggest that insufficiency of Spc42p during meiosis results in a pair of immature nonsister SPBs that are not enclosed by prospore membrane.
authors.affiliation: Department of Integrated Biosciences, Graduate School of Frontier Science, University of Tokyo, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Ishihara
authors.forename: A
authors.initials: A
authors.lastname: Hirata
authors.forename: M
authors.initials: M
authors.lastname: Minemura
authors.forename: S
authors.initials: S
authors.lastname: Nogami
authors.forename: Y
authors.initials: Y
authors.lastname: Ohya
mesh_terms: D015153:Blotting, Western; D003598:Cytoskeletal Proteins / Q000235:genetics* / Q000502:physiology; D004171:Diploidy; D005656:Fungal Proteins / Q000235:genetics* / Q000502:physiology; D005800:Genes, Fungal; D006238:Haploidy; D008540:Meiosis / Q000502:physiology*; D009154:Mutation; D010641:Phenotype; D010750:Phosphoproteins / Q000235:genetics* / Q000502:physiology; D011993:Recombinant Fusion Proteins / Q000502:physiology; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000502:physiology / Q000648:ultrastructure; D029701:Saccharomyces cerevisiae Proteins; D008941:Spindle Apparatus / Q000235:genetics*; D013172:Spores, Fungal
chemical_list: D003598:Cytoskeletal Proteins; D005656:Fungal Proteins; D010750:Phosphoproteins; D011993:Recombinant Fusion Proteins; C432692:SPC42 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins