Summary
Mutants of S. pombe have been isolated which undergo conjugation and sporulation in rich medium, conditions which are normally inhibitory for these processes. Two of these mutants are also able to sporulate from the haploid state in the absence of heterozygosity at the mating type locus. These recessive mutants define a single nuclear gene called ran1 which is unlinked to mating type. It is proposed that the ran1 gene codes for an inhibitor in the control of the initiation of conjugation and sporulation. In wild type cells the inhibitory effect is released by nutritional starvation and heterozygosity at the mating type locus. This allows the cells to proceed to sporulation. The ran1 mutants are unusual in that they attempt to undergo a reductional meiotic division from the haploid state. They are also genetically unstable and generate extragenic suppressors at high frequency.
Similar content being viewed by others
References
Beach DH, Klar AJS (1984) Rearrangements of the transposable mating type cassettes of fission yeast. Embo 3:603–610
Beach D, Nurse P, Egel R (1982) Molecular rearrangement of matingtype genes in fission yeast. Nature 296:682–683
Calvert GR, Dawes IW (1984) Initiation of sporulation in Saccharomyces cerevisiae. Mutations preventing initiation. J Gen Microbiol 130:615–624
Crandall M, Egel R, MacKay V (1977) Physiology of mating in three yeasts. Adv Microb Phys 15:307–398
Dawes IW (1975) Study of cell development using deprepressed mutations. Nature 255:707–708
Dawes IW, Calvert GR (1984) Initiation of sporulation in Saccharomyces cerevisiae. Mutations causing derepressed sporulation and G1 arrest in the cell division cycle. J Gen Microbiol 130:605–613
Egel R (1973) Commitment to meiosis in Fission Yeast. Mol Gen Genet 121:277–284
Egel R, Egel-Mitani M (1974) Premeiotic DNA synthesis in Fission Yeast. Exptl Cell Res 88:127–134
Egel R, Gutz H (1981) Gene activation by copy transposition in mating-type switching of a Homothallic Fission Yeast. Current Genetics 3:5–12
Gutz H, Heslot H, Leupold U, Loprieno N (1974) Schizosaccharomyces pombe. In: King RC (ed) Handbook of Genetics. 1:395–446. Plenum Press, New York
Hopper A, MacKay V (1980) Control of sporulation in yeast: SAD1-a mating-type specific; Unstable alteration that uncouples sporulation from mating-type control. Molec Gen Genet 180:301–314
Iino Y, Yamamoto Y (1985) Mutants of Schizosaccharomyces pombe which sporulate in the haploid state. Molec Gen Genet 198:416–421
Kassir Y, Herskowitz I (1980) A dominant mutation (SAD) bypassing the Requirement for the mating type locus in yeast sporulation. Molec Gen Genet 180:315–322
Klar AJS, Fogel S, Macleod K (1979) MAR1-A regulator of the HMa and HMα Loci in Saccharomyces cerevisiae. Genetics 93:37–50
Matsumoto K, Uno I, Ishikawa T (1983) Initiation of meiosis in yeast mutants defective in adenylate cyclase and cyclic AMP-dependent protein kinase. Cell 32:417–423
Meade JH, Gutz H (1976) Mating-type mutations in Schizosaccharomyces pombe: Isolations of mutants and analysis of strains with an h- or h+ phenotype. Genetics 83:259–273
Mitchison JM (1970) Physiological and cytological methods in Schizosaccharomyces pombe. Methods Cell Physiol 4:131–165
McDonald IJ, Calleja GB, Johnson BF (1982) Conjugation in chemostat cultures of Schizosaccharomyces pombe. J Gen Microbiol 128:1931–1987
Nasmyth K, Nurse P, Fraser RSS (1979) The effect of cell mass on the cell cycle timing and duration of S-phase in fission yeast. J Cell Sci 39:215–233
Nurse P (1975) Genetic control of cell size at cell division in yeast. Nature 256:547–551
Nurse P, Bissett Y (1981) Gene required in G1 for commitment to cell cycle and in G2 for control of mitosis in fission yeast. Nature 292:558–560
Nurse P, Thuriaux P, Nasmyth K (1976) Genetic control of the cell division cycle in the fission yeast Schizosaccharomyces pombe. Molec Gen Genet 146:167–178
Olson LW, Eden U, Egel-Mitani M, Egel R (1978) Asynaptic meiosis in fission yeast. Hereditas 89:189–199
Rine J, Srathern JN, Hicks JB, Herskowitz I (1979) A Suppressor of Mating-Type Locus Mutations in Saccharomyces cerevisiae: Evidence for and identification of cryptic mating type loci. Genetics 93:877–901
Roth R, Fogel S (1971) A system selective for yeast mutants deficient in meiotic recombination. Molec Gen Genet 112:295–305
Shilo V, Simchen G, Shilo B (1978) Initiation of meiosis in cell cycle initiation mutants of Saccharomyces cerevisiae. Exptl Cell Res 112:241–248
Author information
Authors and Affiliations
Additional information
Communicated by C. Auerbach
Rights and permissions
About this article
Cite this article
Nurse, P. Mutants of the fission yeast Schizosaccharomyces pombe which alter the shift between cell proliferation and sporulation. Mol Gen Genet 198, 497–502 (1985). https://doi.org/10.1007/BF00332946
Received:
Revised:
Issue Date:
DOI: https://doi.org/10.1007/BF00332946