Fission yeast minichromosome loss mutants mis cause lethal aneuploidy and replication abnormality.
Precise chromosome transmission in cell division cycle is maintained by a number of genes. The attempt made in the present study was to isolate temperature-sensitive (ts) fission yeast mutants that display high loss rates of minichromosomes at permissive or semipermissive temperature (designated mis). By colony color assay of 539 ts strains that contain a minichromosome, we have identified 12 genetic loci (mis1-mis12) and determined their phenotypes at restrictive temperature. Seven of them are related to cell cycle block phenotype at restrictive temperature, three of them in mitosis. Unequal distribution of regular chromosomes in the daughters is extensive in mis6 and mis12. Cells become inviable after rounds of cell division due to missegregation. The phenotype of mis5 is DNA replication defect and hypersensitivity to UV ray and hydroxyurea. mis5+ encodes a novel member of the ubiquitous MCM family required for the onset of replication. The mis5+ gene is essential for viability and functionally distinct from other previously identified members in fission yeast, cdc21+, nda1+, and nda4+. The mis11 mutant phenotype was the cell division block with reduced cell size. Progression of the G1 and G2 phases is blocked in mis11. The cloned mis11+ gene is identical to prp2+, which is essential for RNA splicing and similar to a mammalian splicing factor U2AF65.
Takahashi
K
K
Department of Biophysics, Faculty of Science, Kyoto University, Japan.
Yamada
H
H
Yanagida
M
M
D000595:Amino Acid Sequence; D000782:Aneuploidy; D001483:Base Sequence; D018797:Cell Cycle Proteins; D002455:Cell Division / Q000235:genetics; D015825:Chromosomes, Fungal; D004261:DNA Replication / Q000235:genetics; D004271:DNA, Fungal / Q000096:biosynthesis / Q000235:genetics; D004268:DNA-Binding Proteins; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D005800:Genes, Fungal; D064148:Minichromosome Maintenance Complex Component 4; D064151:Minichromosome Maintenance Complex Component 6; D008969:Molecular Sequence Data; D009154:Mutation; D010641:Phenotype; D012568:Schizosaccharomyces / Q000166:cytology / Q000235:genetics* / Q000378:metabolism; D029702:Schizosaccharomyces pombe Proteins; D017386:Sequence Homology, Amino Acid; D013696:Temperature
D018797:Cell Cycle Proteins; D004271:DNA, Fungal; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; D029702:Schizosaccharomyces pombe Proteins; C085711:mcm5 protein, S pombe; D064148:Minichromosome Maintenance Complex Component 4; D064151:Minichromosome Maintenance Complex Component 6; C078490:mcm4 protein, S pombe; C092300:mcm6 protein, S pombe