scholarly journals Differential function and expression of Saccharomyces cerevisiae B-type cyclins in mitosis and meiosis.

1993 ◽  
Vol 13 (4) ◽  
pp. 2113-2125 ◽  
Author(s):  
N Grandin ◽  
S I Reed

We have studied the patterns of expression of four B-type cyclins (Clbs), Clb1, Clb2, Clb3, and Clb4, and their ability to activate p34cdc28 during the mitotic and meiotic cell cycles of Saccharomyces cerevisiae. During the mitotic cell cycle, Clb3 and Clb4 were expressed and induced a kinase activity in association with p34cdc28 from early S phase up to mitosis. On the other hand, Clb1 and Clb2 were expressed and activated p34cdc28 later in the mitotic cell cycle, starting in late S phase and continuing up to mitosis. The pattern of expression of Clb3 and Clb4 suggests a possible role in the regulation of DNA replication as well as mitosis. Clb1 and Clb2, whose pattern of expression is similar to that of other known Clbs, are likely to have a role predominantly in the regulation of M phase. During the meiotic cell cycle, Clb1, Clb3, and Clb4 were expressed and induced a p34cdc28-associated kinase activity just before the first meiotic division. The fact that Clb3 and Clb4 were not synthesized earlier, in S phase, suggests that these cyclins, which probably have a role in S phase during the mitotic cell cycle, are not implicated in premeiotic S phase. Clb2, the primary mitotic cyclin in S. cerevisiae, was not detectable during meiosis. Sporulation experiments on strains deleted for one, two, or three Clbs indicate, in agreement with the biochemical data, that Clb1 is the primary cyclin for the regulation of meiosis, while Clb2 is not involved at all.

1993 ◽  
Vol 13 (4) ◽  
pp. 2113-2125
Author(s):  
N Grandin ◽  
S I Reed

We have studied the patterns of expression of four B-type cyclins (Clbs), Clb1, Clb2, Clb3, and Clb4, and their ability to activate p34cdc28 during the mitotic and meiotic cell cycles of Saccharomyces cerevisiae. During the mitotic cell cycle, Clb3 and Clb4 were expressed and induced a kinase activity in association with p34cdc28 from early S phase up to mitosis. On the other hand, Clb1 and Clb2 were expressed and activated p34cdc28 later in the mitotic cell cycle, starting in late S phase and continuing up to mitosis. The pattern of expression of Clb3 and Clb4 suggests a possible role in the regulation of DNA replication as well as mitosis. Clb1 and Clb2, whose pattern of expression is similar to that of other known Clbs, are likely to have a role predominantly in the regulation of M phase. During the meiotic cell cycle, Clb1, Clb3, and Clb4 were expressed and induced a p34cdc28-associated kinase activity just before the first meiotic division. The fact that Clb3 and Clb4 were not synthesized earlier, in S phase, suggests that these cyclins, which probably have a role in S phase during the mitotic cell cycle, are not implicated in premeiotic S phase. Clb2, the primary mitotic cyclin in S. cerevisiae, was not detectable during meiosis. Sporulation experiments on strains deleted for one, two, or three Clbs indicate, in agreement with the biochemical data, that Clb1 is the primary cyclin for the regulation of meiosis, while Clb2 is not involved at all.


2005 ◽  
Vol 25 (15) ◽  
pp. 6330-6337 ◽  
Author(s):  
Jordi Malapeira ◽  
Alberto Moldón ◽  
Elena Hidalgo ◽  
Gerald R. Smith ◽  
Paul Nurse ◽  
...  

ABSTRACT The meiotic cell cycle is modified from the mitotic cell cycle by having a premeiotic S phase which leads to high levels of recombination, a reductional pattern of chromosome segregation at the first division, and a second division with no intervening DNA synthesis. Cyclin-dependent kinases are essential for progression through the meiotic cell cycle, as for the mitotic cycle. Here we show that a fission yeast cyclin, Rem1, is present only during meiosis. Cells lacking Rem1 have impaired meiotic recombination, and Rem1 is required for premeiotic DNA synthesis when Cig2 is not present. rem1 expression is regulated at the level of both transcription and splicing, with Mei4 as a positive and Cig2 a negative factor of rem1 splicing. This regulation ensures the timely appearance of the different cyclins during meiosis, which is required for the proper progression through the meiotic cell cycle. We propose that the meiosis-specific B-type cyclin Rem1 has a central role in bringing about progression through meiosis.


The fission yeast Schizosaccharomyces pombe has been used to identify gene functions required for the cell to become committed to the mitotic cell cycle and to initiate the processes leading to chromosome replication in S-phase. Two gene functions cdc 2 and cdc 10 must be executed for the cell to traverse ‘start’ and proceed from G1 into S-phase. Before the completion of these two functions the cell is in an uncommitted state and can undergo alternative developmental fates such as conjugation. A third gene, sucl, has also been identified whose product may interact directly with that of cdc 2 at ‘start’. The molecular functions of the genes involved in the completion of ‘ start ’ have been investigated. The cdc 2 gene has been shown to be a protein kinase, suggesting that phosphorylation may be involved in the control over the transition from G1 into S-phase. The biochemical functions of the cdc 10 and suc 1 gene products have not yet been elucidated. A control at ‘start’ has also been shown to exist in the budding yeast Saccharomyces cerevisiae . Traverse o f‘start’ requires the execution of the CDC28 gene function. The cdc2 and CDC28 gene products (lower-case letters represent genes of Schizosaccharomyces pombe , and capital letters genes of Saccharomyces cerevisiae ) are functionally homologous, suggesting that the processes involved in traverse o f‘start’ are highly conserved. An analogous control may also exist in the G1 period of mammalian cells, suggesting that the ‘ start ’ control step, after which cells become committed to the mitotic cell cycle, may have been conserved through evolution.


2000 ◽  
Vol 20 (8) ◽  
pp. 2794-2802 ◽  
Author(s):  
Neptune Mizrahi ◽  
Claire Moore

ABSTRACT The poly(A) polymerase of the budding yeast Saccharomyces cerevisiae (Pap1) is a 64-kDa protein essential for the maturation of mRNA. We have found that a modified Pap1 of 90 kDa transiently appears in cells after release from α-factor-induced G1 arrest or from a hydroxyurea-induced S-phase arrest. While a small amount of modification occurs in hydroxyurea-arrested cells, fluorescence-activated cell sorting analysis and microscopic examination of bud formation indicate that the majority of modified enzyme is found at late S/G2 and disappears by the time cells have reached M phase. The reduction of the 90-kDa product upon phosphatase treatment indicates that the altered mobility is due to phosphorylation. A preparation containing primarily the phosphorylated Pap1 has no poly(A) addition activity, but this activity is restored by phosphatase treatment. A portion of Pap1 is also polyubiquitinated concurrent with phosphorylation. However, the bulk of the 64-kDa Pap1 is a stable protein with a half-life of 14 h. The timing, nature, and extent of Pap1 modification in comparison to the mitotic phosphorylation of mammalian poly(A) polymerase suggest an intriguing difference in the cell cycle regulation of this enzyme in yeast and mammalian systems.


2000 ◽  
Vol 149 (1) ◽  
pp. 125-140 ◽  
Author(s):  
Andrew Bloecher ◽  
Kelly Tatchell

Protein phosphatase type I (PP1), encoded by the single essential gene GLC7 in Saccharomyces cerevisiae, functions in diverse cellular processes. To identify in vivo subcellular location(s) where these processes take place, we used a functional green fluorescent protein (GFP)–Glc7p fusion protein. Time-lapse fluorescence microscopy revealed GFP–Glc7p localizes predominantly in the nucleus throughout the mitotic cell cycle, with the highest concentrations in the nucleolus. GFP–Glc7p was also observed in a ring at the bud neck, which was dependent upon functional septins. Supporting a role for Glc7p in bud site selection, a glc7-129 mutant displayed a random budding pattern. In α-factor treated cells, GFP–Glc7p was located at the base of mating projections, again in a septin-dependent manner. At the start of anaphase, GFP–Glc7p accumulated at the spindle pole bodies and remained there until cytokinesis. After anaphase, GFP–Glc7p became concentrated in a ring that colocalized with the actomyosin ring. A GFP–Glc7-129 fusion was defective in localizing to the bud neck and SPBs. Together, these results identify sites of Glc7p function and suggest Glc7p activity is regulated through dynamic changes in its location.


2009 ◽  
Vol 29 (18) ◽  
pp. 4891-4905 ◽  
Author(s):  
Santhi Pondugula ◽  
Daniel W. Neef ◽  
Warren P. Voth ◽  
Russell P. Darst ◽  
Archana Dhasarathy ◽  
...  

ABSTRACT Cells devote considerable resources to nutrient homeostasis, involving nutrient surveillance, acquisition, and storage at physiologically relevant concentrations. Many Saccharomyces cerevisiae transcripts coding for proteins with nutrient uptake functions exhibit peak periodic accumulation during M phase, indicating that an important aspect of nutrient homeostasis involves transcriptional regulation. Inorganic phosphate is a central macronutrient that we have previously shown oscillates inversely with mitotic activation of PHO5. The mechanism of this periodic cell cycle expression remains unknown. To date, only two sequence-specific activators, Pho4 and Pho2, were known to induce PHO5 transcription. We provide here evidence that Mcm1, a MADS-box protein, is essential for PHO5 mitotic activation. In addition, we found that cells simultaneously lacking the forkhead proteins, Fkh1 and Fkh2, exhibited a 2.5-fold decrease in PHO5 expression. The Mcm1-Fkh2 complex, first shown to transactivate genes within the CLB2 cluster that drive G2/M progression, also associated directly at the PHO5 promoter in a cell cycle-dependent manner in chromatin immunoprecipitation assays. Sds3, a component specific to the Rpd3L histone deacetylase complex, was also recruited to PHO5 in G1. These findings provide (i) further mechanistic insight into PHO5 mitotic activation, (ii) demonstrate that Mcm1-Fkh2 can function combinatorially with other activators to yield late M/G1 induction, and (iii) couple the mitotic cell cycle progression machinery to cellular phosphate homeostasis.


2019 ◽  
Author(s):  
Yu-Ying Phoebe Hsieh ◽  
Vasso Makrantoni ◽  
Daniel Robertson ◽  
Adèle L Marston ◽  
Andrew W Murray

AbstractDifferent members of the same protein family often perform distinct cellular functions. How much are these differing functions due to changes in a protein’s biochemical activity versus changes in other proteins? We asked how the budding yeast, Saccharomyces cerevisiae, evolves when forced to use the meiosis-specific kleisin, Rec8, instead of the mitotic kleisin, Scc1, during the mitotic cell cycle. This perturbation impairs sister chromosome linkage and reduces reproductive fitness by 45%. We evolved 15 populations for 1750 generations, substantially increasing their fitness, and analyzed their genotypes and phenotypes. We found no mutations in Rec8, but many populations had mutations in the transcriptional mediator complex, cohesin-related genes, and cell cycle regulators that induce S phase. These mutations improve sister chromosome cohesion and slow genome replication in Rec8-expressing cells. We conclude that changes in known and novel partners allow proteins to improve their ability to perform new functions.


Development ◽  
1991 ◽  
Vol 113 (3) ◽  
pp. 789-795 ◽  
Author(s):  
T. Choi ◽  
F. Aoki ◽  
M. Mori ◽  
M. Yamashita ◽  
Y. Nagahama ◽  
...  

p34cdc2 protein kinase is a universal regulator of M-phase in eukaryotic cell cycle. To investigate the regulation of meiotic and mitotic cell cycle in mammals, we examined the changes in phosphorylation states of p34cdc2 and its histone H1 kinase activity in mouse oocytes and embryos. We showed that p34cdc2 has three different migrating bands (referred to as upper, middle and lower bands) on SDS-PAGE followed by immunoblotting with anti-PSTAIR antibody, and that the upper and middle bands are phosphorylated forms since these two bands shifted to the lower one by alkaline phosphatase treatment. In meiotic cell cycle, only germinal vesicle (GV) stage oocytes had the three forms. The phosphorylated forms decreased gradually in oocytes up to 2 h after isolation from follicles, and thereafter the phosphorylation states did not change significantly until metaphase II. However, the histone H1 kinase activity oscillated, being activated at the first and second metaphase in meiosis and inactivated at the time of the first polar body extrusion. These results suggest that changes in phosphorylation states of p34cdc2 triggered its activation at the first metaphase, but not inactivation and reactivation at the first and second metaphase, respectively. In mitotic cell cycle, phosphorylated forms appeared at 4 h after insemination, increased greatly just before metaphase, and were dephosphorylated in metaphase. Histone H1 kinase activity was high only at metaphase. This kinase activation is probably triggered by dephosphorylation of p34cdc2.


Development ◽  
1999 ◽  
Vol 126 (10) ◽  
pp. 2227-2239 ◽  
Author(s):  
M. Boxem ◽  
D.G. Srinivasan ◽  
S. van den Heuvel

We have identified six protein kinases that belong to the family of cdc2-related kinases in Caenorhabditis elegans. Results from RNA interference experiments indicate that at least one of these kinases is required for cell-cycle progression during meiosis and mitosis. This kinase, encoded by the ncc-1 gene, is closely related to human Cdk1/Cdc2, Cdk2 and Cdk3 and yeast CDC28/cdc2(+). We addressed whether ncc-1 acts to promote passage through a single transition or multiple transitions in the cell cycle, analogous to Cdks in vertebrates or yeasts, respectively. We isolated five recessive ncc-1 mutations in a genetic screen for mutants that resemble larval arrested ncc-1(RNAi) animals. Our results indicate that maternal ncc-1 product is sufficient for embryogenesis, and that zygotic expression is required for cell divisions during larval development. Cells that form the postembryonic lineages in wild-type animals do not enter mitosis in ncc-1 mutants, as indicated by lack of chromosome condensation and nuclear envelope breakdown. However, progression through G1 and S phase appears unaffected, as revealed by expression of ribonucleotide reductase, incorporation of BrdU and DNA quantitation. Our results indicate that C. elegans uses multiple Cdks to regulate cell-cycle transitions and that ncc-1 is the C. elegans ortholog of Cdk1/Cdc2 in other metazoans, required for M phase in meiotic as well as mitotic cell cycles.


1989 ◽  
Vol 92 (1) ◽  
pp. 51-56 ◽  
Author(s):  
V. Simanis ◽  
P. Nurse

We have used antiserum raised against a beta-galactosidase-cdc10+ fusion protein to identify the protein product of the cdc10+ start gene of Schizosaccharomyces pombe. This gene is required for progress through the G1 phase of the cell cycle and for activating processes such as the increase in histone mRNA level in preparation for S phase. The protein has an apparent molecular weight of 87,000 and is phosphorylated on multiple serine residues. The protein remains phosphorylated throughout the mitotic cell cycle and shows no significant steady-state changes in level. The antiserum has also detected a protein similar in size to p87cdc10 in human cells.


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