title: SSP1, a gene necessary for proper completion of meiotic divisions and spore formation in Saccharomyces cerevisiae.
abstract: During meiosis, a diploid cell undergoes two rounds of nuclear division following one round of DNA replication to produce four haploid gametes. In yeast, haploid meiotic products are packaged into spores. To gain new insights into meiotic development and spore formation, we followed differential expression of genes in meiotic versus vegetatively growing cells in the yeast Saccharomyces cerevisiae. Our results indicate that there are at least five different classes of transcripts representing genes expressed at different stages of the sporulation program. Here we describe one of these differentially expressed genes, SSP1, which plays an essential role in meiosis and spore formation. SSP1 is expressed midway through meiosis, and homozygous ssp1 diploid cells fail to sporulate. In the ssp1 mutant, meiotic recombination is normal but viability declines rapidly. Both meiotic divisions occur at the normal time; however, the fraction of cells completing meiosis is significantly reduced, and nuclei become fragmented soon after meiosis II. The ssp1 defect does not appear to be related to a microtubule-cytoskeletal-dependent event and is independent of two rounds of chromosome segregation. The data suggest that Ssp1 is likely to function in a pathway that controls meiotic nuclear divisions and coordinates meiosis and spore formation.
authors.affiliation: Wadsworth Center, and Department of Biomedical Sciences, School of Public Health, State University of New York, Albany 12201, USA. dilip.nag@wadsworth.org
authors.forename: D K
authors.initials: DK
authors.lastname: Nag
authors.forename: M P
authors.initials: MP
authors.lastname: Koonce
authors.forename: J
authors.initials: J
authors.lastname: Axelrod
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D018797:Cell Cycle Proteins; D002874:Chromosome Mapping; D053938:DNA Fragmentation; D004271:DNA, Fungal / Q000235:genetics; D005656:Fungal Proteins / Q000235:genetics*; D015966:Gene Expression Regulation, Fungal; D005800:Genes, Fungal; D005821:Genetic Techniques; D008540:Meiosis / Q000235:genetics*; D008969:Molecular Sequence Data; D009154:Mutation; D010641:Phenotype; D012331:RNA, Fungal / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics; D011995:Recombination, Genetic; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000235:genetics* / Q000502:physiology; D029701:Saccharomyces cerevisiae Proteins; D013172:Spores, Fungal / Q000235:genetics* / Q000502:physiology
chemical_list: D018797:Cell Cycle Proteins; D004271:DNA, Fungal; D005656:Fungal Proteins; D012331:RNA, Fungal; D012333:RNA, Messenger; C051095:SSP1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins