scholarly journals AN ENDOMITOTIC EFFECT OF A CELL CYCLE MUTATION OF SACCHAROMYCES CEREVISIAE

Genetics ◽  
1981 ◽  
Vol 97 (3-4) ◽  
pp. 551-562 ◽  
Author(s):  
David Schild ◽  
Honnavara N Ananthaswamy ◽  
Robert K Mortimer
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Genetic Analysis ◽  
Nuclear Division ◽  
Pedigree Analysis ◽  
Visual Observation ◽  
Temperature Sensitive ◽  
Cell Stage ◽  
Haploid Strain ◽  
A Cell ◽  
Dna Measurements

ABSTRACT A recessive temperature-sensitive mutation of Saccharomyces cerevisiae has been isolated and shown to cause an increase in ploidy in both haploids and diploids. Genetic analysis revealed that the strain carrying the mutation was an aa diploid, although MNNG mutagenesis had been done on an a haploid strain. When the mutant strain was crossed with an aa diploid and the resultant tetraploid sporulated, some of the meiotic progeny of this tetraploid were themselves tetraploid, as shown by both genetic analysis and DNA measurements, instead of diploid as expected of tetraploid meiosis. The ability of these tetraploids to continue to produce tetraploid meiotic progeny was followed for four generations. Homothallism was excluded as a cause of the increase in ploidy; visual pedigree analysis of spore clones to about the 32-cell stage failed to reveal any zygotes, and haploids that diploidized retained their mating type. An extra round of meiotic DNA synthesis was also considered and excluded. It was found that tetraploidization was independent of sporulation temperature, but was dependent on the temperature of germination and the growth of the spores. Increase in ploidy occurred when the spores were germinated and grown at 30°, but did not occur at 23°. Two cycles of sporulation and growth at 23° resulted in haploids, which were shown to diploidize within 24 hr when grown at 30°. Visual observation of the haploid cells incubated at 36° revealed a celldivisioncycle phenotype characteristic of mutations that affect nuclear division; complementation analysis demonstrated that the mutation, cdc31-2, is allelic to cdc31-1, a mutation isolated by HARTWEeLL et al.(1973) and characterized as causing a temperature-sensitive arrest during late nuclear division. The segregation of cdc31-2 in heterozygous diploids was 2:2 and characteristic of a noncentromere-linked gene.

scholarly journals MITOCHONDRIAL GENETIC ANALYSIS BY ZYGOTE CELL LINEAGES IN SACCHAROMYCES CEREVISIAE

Genetics ◽  
1973 ◽  
Vol 73 (3) ◽  
pp. 367-377
Author(s):  
D Wilkie ◽  
D Y Thomas
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Genetic Analysis ◽  
Pedigree Analysis ◽  
Cell Lineages ◽  
Mitochondrial Markers ◽  
Yeast Strains ◽  
Oligomycin A ◽  
Multiple Recombination

ABSTRACT Yeast strains were constructed carrying multiple mitochondrial markers conferring resistance to the inhibitors erythromycin, chloramphenicol, paromomycin and oligomycin. A pedigree analysis of two crosses was made by micromanipulating buds from zygotes. The first few daughter buds isolated from the zygotes sometimes gave rise to diploid clones which had a mixture of mitochondrial types. All possible classes of mitochondrial parental and recombinant types were found although they never appeared all together as the progeny from a single zygote. It was inferred that multiple recombination events took place in zygotes and in some of the buds derived from them. After removal of the first four or so daughter buds, subsequent buds from the zygote carried one mitochondrial type only. In cross I in which three markers were analyzed this was most frequently one of the parental types. In cross II (involving four mitochondrial markers) the later buds from the zygotes were frequently of recombinant mitochondrial type.

scholarly journals Saccharomyces cerevisiae cdc15 mutants arrested at a late stage in anaphase are rescued by Xenopus cDNAs encoding N-ras or a protein with beta-transducin repeats.

1993 ◽  
Vol 13 (8) ◽  
pp. 4953-4966 ◽  
Author(s):  
W Spevak ◽  
B D Keiper ◽  
C Stratowa ◽  
M J Castañón
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Cycle ◽  
Yeast Cells ◽  
Cell Cycle Gene ◽  
Intracellular Camp ◽  
Temperature Sensitive ◽  
Ras Genes ◽  
Phosphorylation Event ◽  
Dependent Protein ◽  
A Cell

We have constructed a Xenopus oocyte cDNA library in a Saccharomyces cerevisiae expression vector and used this library to isolate genes that can function in yeast cells to suppress the temperature sensitive [corrected] defect of the cdc15 mutation. Two maternally expressed Xenopus cDNAs which fulfill these conditions have been isolated. One of these clones encodes Xenopus N-ras. In contrast to the yeast RAS genes, Xenopus N-ras rescues the cdc15 mutation. Moreover, overexpression of Xenopus N-ras in S. cerevisiae does not activate the RAS-cyclic AMP (cAMP) pathway; rather, it results in decreased levels of intracellular cAMP in both mutant cdc15 and wild-type cells. Furthermore, we show that lowering cAMP levels is sufficient to allow cells with a nonfunctional Cdc15 protein to complete the mitotic cycle. These results suggest that a key step of the cell cycle is dependent upon a phosphorylation event catalyzed by cAMP-dependent protein kinase. The second clone, beta TrCP (beta-transducin repeat-containing protein), encodes a protein of 518 amino acids that shows significant homology to the beta subunits of G proteins in its C-terminal half. In this region, beta Trcp is composed of seven beta-transducin repeats. beta TrCP is not a functional homolog of S. cerevisiae CDC20, a cell cycle gene that also contains beta-transducin repeats and suppresses the cdc15 mutation.

scholarly journals Regulation of the Anaphase-promoting Complex/Cyclosome bybimA APC3 and Proteolysis of NIMA

1998 ◽  
Vol 9 (11) ◽  
pp. 3019-3030 ◽  
Author(s):  
Xiang S. Ye ◽  
Russell R. Fincher ◽  
Alice Tang ◽  
Aysha H. Osmani ◽  
Stephen A. Osmani
Keyword(s):  
Cell Cycle ◽  
Kinase Activity ◽  
Nuclear Division ◽  
Temperature Sensitive ◽  
Dependent Manner ◽  
Anaphase Promoting Complex ◽  
A Cell ◽  
Protein Instability ◽  
Clock Mechanism ◽  
Very High

Surprisingly, although highly temperature-sensitive, thebimA1 APC3 anaphase-promoting complex/cyclosome (APC/C) mutation does not cause arrest of mitotic exit. Instead, rapid inactivation ofbimA1 APC3 is shown to promote repeating oscillations of chromosome condensation and decondensation, activation and inactivation of NIMA and p34cdc2 kinases, and accumulation and degradation of NIMA, which all coordinately cycle multiple times without causing nuclear division. ThesebimA1 APC3-induced cell cycle oscillations require active NIMA, because a nimA5 +bimA1 APC3 double mutant arrests in a mitotic state with very high p34cdc2 H1 kinase activity. NIMA protein instability during S phase and G2 was also found to be controlled by the APC/C. The bimA1 APC3mutation therefore first inactivates the APC/C but then allows its activation in a cyclic manner; these cycles depend on NIMA. We hypothesize that bimA APC3 could be part of a cell cycle clock mechanism that is reset after inactivation ofbimA1 APC3. ThebimA1 APC3 mutation may also make the APC/C resistant to activation by mitotic substrates of the APC/C, such as cyclin B, Polo, and NIMA, causing mitotic delay. Once these regulators accumulate, they activate the APC/C, and cells exit from mitosis, which then allows this cycle to repeat. The data indicate thatbimA APC3 regulates the APC/C in a NIMA-dependent manner.

CDP1, a Novel Saccharomyces cerevisiae Gene Required for Proper Nuclear Division and Chromosome Segregation

Genetics ◽  
1996 ◽  
Vol 144 (4) ◽  
pp. 1387-1397 ◽  
Author(s):  
Pamela K Foreman ◽  
Ronald W Davis
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Chromosome Segregation ◽  
Nuclear Division ◽  
Immunofluorescent Staining ◽  
Temperature Sensitive ◽  
Permissive Temperature ◽  
Mitotic Spindles ◽  
Wild Type ◽  
New Gene ◽  
Mutant Cells

To identify new gene products involved in chromosome segregation, we isolated Saccharomyces cerevisiae mutants that require centromere binding factor I (Cbf1p) for viability. One Cbf1p-dependent mutant (denoted cdp1-1) was selected for further analysis. The CDP1 gene encodes a novel 125-kD protein that is notably similar to previously identified mouse, human and Caenorhabditis elegans proteins. CDP1Δ and cdp1-1 mutant cells were temperature sensitive for growth. At the permissive temperature, cdp1-1 and cdp1Δ cells lost chromosomes at a frequencies ∼20-fold and ∼110-fold higher than wild-type cells, respectively. These mutants also displayed unusually long and numerous bundles of cytoplasmic microtubules as revealed by immunofluorescent staining. In addition, we occasionally observed improperly oriented mitotic spindles, residing entirely within one of the cells. Presumably as a result of undergoing nuclear division with improperly oriented spindles, a large percentage of cdp1 cells had accumulated multiple nuclei. While cdp1 mutant cells were hypersensitive to the microtubule-disrupting compound thiabendazole, they showed increased resistance to the closely related compound benomyl relative to wild-type cells. Taken together, these results suggest that Cdp1p plays a role in governing tubulin dynamics within the cell and may interact directly with microtubules or tubulin.

scholarly journals ARE MITOTIC FUNCTIONS REQUIRED IN MEIOSIS?

Genetics ◽  
1974 ◽  
Vol 76 (4) ◽  
pp. 745-753
Author(s):  
G Simchen
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Nuclear Division ◽  
Mitotic Cell ◽  
Intragenic Recombination ◽  
Temperature Sensitive ◽  
Restrictive Temperature ◽  
Mitotic Cell Cycle ◽  
Permissive Temperature ◽  
Meiotic Behavior ◽  
Group I

ABSTRACT Sporulation of diploid yeasts (Saccharomyces cerevisiae), homozygous or heterozygous for temperature-sensitive mitotic cell-cycle mutations, was examined at the restrictive and permissive temperatures. Twenty genes, represented by 32 heterozygotes and 60 homozygotes, were divided into three groups, showing (i) normal sporulation, (ii) no sporulation at the restrictive temperature but normal sporulation at the permissive temperature, (iii) no sporulation at both temperatures. Group (i) as well as several other strains were tested for their meiotic behavior with regard to intragenic recombination and haploidization. The conclusion reached was that all the mitotic nuclear-division and DNA-synthesis functions were required in meiosis. The only cell-division mutations not to affect meiosis were in three cytokinesis loci and in one budemergence locus.

scholarly journals Molecular and genetic analysis of the SNF7 gene in Saccharomyces cerevisiae.

Genetics ◽  
1993 ◽  
Vol 135 (1) ◽  
pp. 17-23 ◽  
Author(s):  
J Tu ◽  
L G Vallier ◽  
M Carlson
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Genetic Analysis ◽  
Growth Defect ◽  
Temperature Sensitive ◽  
Chromosomal Locus ◽  
Glucose Limitation ◽  
Suppressor Mutations ◽  
Invertase Gene ◽  
The Right ◽  
Synthetic Phenotype

Abstract Mutations in the SNF7 gene of Saccharomyces cerevisiae prevent full derepression of the SUC2 (invertase) gene in response to glucose limitation. We report the molecular cloning of the SNF7 gene by complementation. Sequence analysis predicts that the gene product is a 27-kDa acidic protein. Disruption of the chromosomal locus causes a fewfold decrease in invertase derepression, a growth defect on raffinose, temperature-sensitive growth on glucose, and a sporulation defect in homozygous diploids. Genetic analysis of the interactions of the snf7 null mutation with ssn6 and spt6/ssn20 suppressor mutations distinguished SNF7 from the SNF2, SNF5 and SNF6 genes. The snf7 mutation also behaved differently from mutations in SNF1 and SNF4 in that snf7 ssn6 double mutants displayed a synthetic phenotype of severe temperature sensitivity for growth. We also mapped SNF7 to the right arm of chromosome XII near the centromere.

scholarly journals Accumulation of mRNA Coding for the Ctf13p Kinetochore Subunit of Saccharomyces cerevisiae Depends on the Same Factors That Promote Rapid Decay of Nonsense mRNAs

Genetics ◽  
1998 ◽  
Vol 150 (3) ◽  
pp. 1019-1035
Author(s):  
Jeffrey N Dahlseid ◽  
John Puziss ◽  
Renee L Shirley ◽  
Audrey L Atkin ◽  
Philip Hieter ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Stop Codon ◽  
Mrna Level ◽  
Premature Stop Codon ◽  
Temperature Sensitive ◽  
Restrictive Temperature ◽  
Rapid Decay ◽  
Mrna Accumulation ◽  
Haploid Strain ◽  
Kinetochore Function

Abstract The CTF13 gene codes for a subunit of the kinetochore in Saccharomyces cerevisiae. The temperature-sensitive mutation ctf13-30, which confers reduced fidelity of chromosome transmission, is a G → A transition causing an amino acid substitution of Lys for Glu146. Strains carrying one chromosomal copy of ctf13-30 fail to grow at the restrictive temperature, whereas a haploid strain carrying two copies of ctf13-30 can grow. Four genes, UPF1, UPF2, UPF3, and ICK1, were represented among extragenic suppressors of ctf13-30. The UPF genes encode proteins that promote rapid decay of pre-mRNAs and mRNAs containing a premature stop codon. Suppressor mutations in these genes restore kinetochore function by causing increased accumulation of ctf13-30 mRNA. They also cause increased accumulation of CYH2 pre-mRNA, which is a natural target of UPF-mediated decay. Mutations in ICK1 restore kinetochore function but have no effect on ctf13-30 mRNA or CYH2 pre-mRNA accumulation. Most importantly, loss of UPF1 function causes increased accumulation of wild-type CTF13 mRNA but has no effect on the mRNA half-life. We propose that UPF-mediated decay modulates the mRNA level of one or more factors involved in CTF13 mRNA expression.

Saccharomyces cerevisiae cdc15 mutants arrested at a late stage in anaphase are rescued by Xenopus cDNAs encoding N-ras or a protein with beta-transducin repeats

1993 ◽  
Vol 13 (8) ◽  
pp. 4953-4966
Author(s):  
W Spevak ◽  
B D Keiper ◽  
C Stratowa ◽  
M J Castañón
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Cycle ◽  
Yeast Cells ◽  
Cell Cycle Gene ◽  
Intracellular Camp ◽  
Temperature Sensitive ◽  
Ras Genes ◽  
Phosphorylation Event ◽  
Dependent Protein ◽  
A Cell

We have constructed a Xenopus oocyte cDNA library in a Saccharomyces cerevisiae expression vector and used this library to isolate genes that can function in yeast cells to suppress the temperature sensitive [corrected] defect of the cdc15 mutation. Two maternally expressed Xenopus cDNAs which fulfill these conditions have been isolated. One of these clones encodes Xenopus N-ras. In contrast to the yeast RAS genes, Xenopus N-ras rescues the cdc15 mutation. Moreover, overexpression of Xenopus N-ras in S. cerevisiae does not activate the RAS-cyclic AMP (cAMP) pathway; rather, it results in decreased levels of intracellular cAMP in both mutant cdc15 and wild-type cells. Furthermore, we show that lowering cAMP levels is sufficient to allow cells with a nonfunctional Cdc15 protein to complete the mitotic cycle. These results suggest that a key step of the cell cycle is dependent upon a phosphorylation event catalyzed by cAMP-dependent protein kinase. The second clone, beta TrCP (beta-transducin repeat-containing protein), encodes a protein of 518 amino acids that shows significant homology to the beta subunits of G proteins in its C-terminal half. In this region, beta Trcp is composed of seven beta-transducin repeats. beta TrCP is not a functional homolog of S. cerevisiae CDC20, a cell cycle gene that also contains beta-transducin repeats and suppresses the cdc15 mutation.

scholarly journals TWO CELL DIVISION CYCLE MUTANTS OF SACCHAROMYCES CEREVISIAE ARE DEFECTIVE IN TRANSMISSION OF MITOCHONDRIA TO ZYGOTES

Genetics ◽  
1982 ◽  
Vol 102 (1) ◽  
pp. 9-17
Author(s):  
Susan K Dutcher
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Cycle ◽  
Nuclear Division ◽  
The Other ◽  
Temperature Sensitive ◽  
Gene Products ◽  
Wild Type ◽  
Mitochondrial Movement ◽  
Mitochondrial Transmission ◽  
Cdc Genes

ABSTRACT Mutations in CDC genes of S. cerevisiae disrupt the cell cycle at specific stages. The experiments reported here demonstrate that two CDC genes, CDC5 and CDC27, are necessary for mitochondrial segregation as well as for nuclear division. The defect in the transmission of mitochondria was revealed by the examination of uninucleate and binucleate progeny of transient heterokaryons generated by using the kar1-1 mutation that disrupts nuclear fusion. One of the parents lacked mitochondrial DNA (?0) whereas the other parent had functional mitochondria (?+). When the parents of the heterokaryon were both wild-type (CDC), nearly all progeny received mitochondria at 21° and at 34°. Thirty-four of the 36 cdc mutations tested had no defect in transmission of mitochondria to zygotic progeny in crosses in which one parent was a cdc mutant and the other parent was not (CDC). However, the cdc5 and cdc27 mutations prevented the transmission of mitochondria to cdc progeny at 34° but not at 21°; CDC progeny received mitochondria at either temperature. This defect was observed in crosses of cdc5 or cdc27 by wild-type cells regardless of which parent donated mitochondria to the zygote. The defect in mitochondrial transmission cosegregated in meiotic tetrads with the defect in mitosis demonstrating that both are likely to be caused by the same temperature-sensitive mutation. These results indicate that the CDC5 and CDC27 gene products are essential in two motility-related processes: mitochondrial movement from the zygote to the progeny and in mitosis.—Furthermore, the results suggest that the function performed by the CDC5 and CDC27 gene products for mitochondrial transmission differ in some fundamental way from the function performed for mitosis. The function necessary for mitosis can be supplied to the cdc5 (or cdc27) nucleus by the CDC5 (or CDC27) nucleus in the same heterokaryon but the function necessary for mitochondrial transmission cannot. Perhaps the function needed for mitochondrial transmission must be performed in the cell cycle preceding the actual segregation of mitochondria whereas the function needed for nuclear segregation can be performed at the time that mitosis occurs.

scholarly journals A Link between Secretion and Pre-mRNA Processing Defects in Saccharomyces cerevisiae and the Identification of a Novel Splicing Gene, RSE1

1998 ◽  
Vol 18 (12) ◽  
pp. 7139-7146 ◽  
Author(s):  
Esther J. Chen ◽  
Alison R. Frand ◽  
Elizabeth Chitouras ◽  
Chris A. Kaiser
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Secretory Pathway ◽  
Small Gtpase ◽  
Mrna Splicing ◽  
Secretory Proteins ◽  
Temperature Sensitive ◽  
Restrictive Temperature ◽  
Golgi Transport ◽  
Pathway Function ◽  
A Cell

ABSTRACT Secretory proteins in eukaryotic cells are transported to the cell surface via the endoplasmic reticulum (ER) and the Golgi apparatus by membrane-bounded vesicles. We screened a collection of temperature-sensitive mutants of Saccharomyces cerevisiaefor defects in ER-to-Golgi transport. Two of the genes identified in this screen were PRP2, which encodes a known pre-mRNA splicing factor, and RSE1, a novel gene that we show to be important for pre-mRNA splicing. Both prp2-13 andrse1-1 mutants accumulate the ER forms of invertase and the vacuolar protease CPY at restrictive temperature. The secretion defect in each mutant can be suppressed by increasing the amount ofSAR1, which encodes a small GTPase essential for COPII vesicle formation from the ER, or by deleting the intron from theSAR1 gene. These data indicate that a failure to spliceSAR1 pre-mRNA is the specific cause of the secretion defects in prp2-13 and rse1-1. Moreover, these data imply that Sar1p is a limiting component of the ER-to-Golgi transport machinery and suggest a way that secretory pathway function might be coordinated with the amount of gene expression in a cell.

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