scholarly journals CDC36 and CDC39 are negative elements in the signal transduction pathway of yeast.

1990 ◽  
Vol 1 (5) ◽  
pp. 391-401 ◽  
Author(s):  
A M Neiman ◽  
F Chang ◽  
K Komachi ◽  
I Herskowitz
Keyword(s):  
Cell Cycle ◽  
Signal Transduction Pathway ◽  
Yeast Cells ◽  
Control Synthesis ◽  
Temperature Sensitive ◽  
G1 Arrest ◽  
Epistasis Analysis ◽  
Cycle Arrest ◽  
Mating Factor ◽  
Inducible Gene

Mutations in either the CDC36 or CDC39 gene cause yeast cells to arrest in G1 of the cell cycle at the same point as treatment with mating pheromone. We demonstrate here that strains harboring temperature-sensitive mutations in CDC36 or CDC39 activate expression of the pheromone-inducible gene FUS1 when shifted to nonpermissive temperature. We show further that cell-cycle arrest and induction of FUS1 are dependent on known components of the mating factor response pathway, the STE genes. Thus, the G1-arrest phenotype of cdc36 and cdc39 mutants results from activation of the mating factor response pathway. The CDC36 and CDC39 gene products behave formally as negative elements in the response pathway: they are required to block response in the absence of pheromone. Epistasis analysis of mutants defective in CDC36 or CDC39 and different STE genes demonstrates that activation requires the response pathway G protein and suggests that CDC36 and CDC39 products may control synthesis or function of the G alpha subunit.

scholarly journals Antagonistic regulation of Fus2p nuclear localization by pheromone signaling and the cell cycle

2009 ◽  
Vol 184 (3) ◽  
pp. 409-422 ◽  
Author(s):  
Casey A. Ydenberg ◽  
Mark D. Rose
Keyword(s):  
Cell Cycle ◽  
S Phase ◽  
Yeast Cells ◽  
Transcriptional Level ◽  
G1 Arrest ◽  
Cycle Arrest ◽  
Pheromone Signaling ◽  
Dependent Inhibition ◽  
Induced Proteins ◽  
Mating Projection

When yeast cells sense mating pheromone, they undergo a characteristic response involving changes in transcription, cell cycle arrest in early G1, and polarization along the pheromone gradient. Cells in G2/M respond to pheromone at the transcriptional level but do not polarize or mate until G1. Fus2p, a key regulator of cell fusion, localizes to the tip of the mating projection during pheromone-induced G1 arrest. Although Fus2p was expressed in G2/M cells after pheromone induction, it accumulated in the nucleus until after cell division. As cells arrested in G1, Fus2p was exported from the nucleus and localized to the nascent tip. Phosphorylation of Fus2p by Fus3p was required for Fus2p export; cyclin/Cdc28p-dependent inhibition of Fus3p during late G1 through S phase was sufficient to block exit. However, during G2/M, when Fus3p was activated by pheromone signaling, Cdc28p activity again blocked Fus2p export. Our results indicate a novel mechanism by which pheromone-induced proteins are regulated during the transition from mitosis to conjugation.

scholarly journals Temperature-Sensitive Lethal Pseudorevertants of ste Mutations in Saccharomyces cerevisiae

Genetics ◽  
1987 ◽  
Vol 115 (4) ◽  
pp. 627-636
Author(s):  
Margaret E Katz ◽  
Jill Ferguson ◽  
Steven I Reed
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Cycle ◽  
Complementation Group ◽  
Temperature Sensitive ◽  
G1 Arrest ◽  
Pheromone Response ◽  
Cycle Arrest ◽  
Homogeneous Cell ◽  
Complementation Groups ◽  
Mutant Cells

ABSTRACT A procedure was devised to isolate mutations that could restore conjugational competence to temperature sensitive ste mutants and simultaneously confer temperature-sensitive lethal growth phenotypes. Three such mutations, falling into two complementation groups, were identified on the basis of suppression of ste5 alleles. These same mutations were later shown to be capable of suppressing ste4 and ste7 alleles. Five mutations in a single complementation group were isolated as suppressors of ste2 alleles. None of the mutations described in this study conferred a homogeneous cell cycle arrest phenotype, and all were shown to define complementation groups distinct from those previously identified in studies of cell division cycle (cdc) mutations. In no instance did pseudoreversion appear to be achieved by mutational G1 arrest of ste mutant cells. Instead, it is proposed that the mutations restore conjugation by reestablishing the normal pheromone response.

scholarly journals FAR1 is required for posttranscriptional regulation of CLN2 gene expression in response to mating pheromone.

1993 ◽  
Vol 13 (2) ◽  
pp. 1013-1022 ◽  
Author(s):  
M H Valdivieso ◽  
K Sugimoto ◽  
K Y Jahng ◽  
P M Fernandes ◽  
C Wittenberg
Keyword(s):  
Cell Cycle ◽  
Posttranscriptional Regulation ◽  
Signal Transduction Pathway ◽  
Yeast Cells ◽  
Pheromone Response ◽  
Transcript Accumulation ◽  
Mating Pheromone ◽  
Cycle Arrest ◽  
Feedback Pathway ◽  
Posttranscriptional Level

Yeast cells arrest during the G1 interval of the cell cycle in response to peptide mating pheromones. The FAR1 gene is required for cell cycle arrest but not for a number of other aspects of the pheromone response. Genetic evidence suggests that FAR1 is required specifically for inactivation of the G1 cyclin CLN2. From these observations, the FAR1 gene has been proposed to encode an element of the interface between the mating pheromone signal transduction pathway and the cell cycle regulatory apparatus. We show here that FAR1 is necessary for the decrease in CLN1 and CLN2 transcript accumulation observed in response to mating pheromone but is unnecessary for regulation of the same transcripts during vegetative growth. However, the defect in regulation of CLN1 expression is dependent upon CLN2. We show that pheromone regulates the abundance of Cln2 at a posttranscriptional level and that FAR1 is required for that regulation. From these observations, we suggest that FAR1 function is limited to posttranscriptional regulation of CLN2 expression by mating pheromone. The failure of mating pheromone to repress CLN2 transcript levels in far1 mutants can be explained by the stimulatory effect of the persistent Cln2 protein on CLN2 transcription via the CLN/CDC28-dependent feedback pathway.

FAR1 is required for posttranscriptional regulation of CLN2 gene expression in response to mating pheromone

1993 ◽  
Vol 13 (2) ◽  
pp. 1013-1022
Author(s):  
M H Valdivieso ◽  
K Sugimoto ◽  
K Y Jahng ◽  
P M Fernandes ◽  
C Wittenberg
Keyword(s):  
Cell Cycle ◽  
Posttranscriptional Regulation ◽  
Signal Transduction Pathway ◽  
Yeast Cells ◽  
Pheromone Response ◽  
Transcript Accumulation ◽  
Mating Pheromone ◽  
Cycle Arrest ◽  
Feedback Pathway ◽  
Posttranscriptional Level

Yeast cells arrest during the G1 interval of the cell cycle in response to peptide mating pheromones. The FAR1 gene is required for cell cycle arrest but not for a number of other aspects of the pheromone response. Genetic evidence suggests that FAR1 is required specifically for inactivation of the G1 cyclin CLN2. From these observations, the FAR1 gene has been proposed to encode an element of the interface between the mating pheromone signal transduction pathway and the cell cycle regulatory apparatus. We show here that FAR1 is necessary for the decrease in CLN1 and CLN2 transcript accumulation observed in response to mating pheromone but is unnecessary for regulation of the same transcripts during vegetative growth. However, the defect in regulation of CLN1 expression is dependent upon CLN2. We show that pheromone regulates the abundance of Cln2 at a posttranscriptional level and that FAR1 is required for that regulation. From these observations, we suggest that FAR1 function is limited to posttranscriptional regulation of CLN2 expression by mating pheromone. The failure of mating pheromone to repress CLN2 transcript levels in far1 mutants can be explained by the stimulatory effect of the persistent Cln2 protein on CLN2 transcription via the CLN/CDC28-dependent feedback pathway.

scholarly journals Slm9, a Novel Nuclear Protein Involved in Mitotic Control in Fission Yeast

Genetics ◽  
2000 ◽  
Vol 155 (2) ◽  
pp. 623-631
Author(s):  
Junko Kanoh ◽  
Paul Russell
Keyword(s):  
Cell Cycle ◽  
Fission Yeast ◽  
Cell Elongation ◽  
Nuclear Protein ◽  
G1 Arrest ◽  
Permissive Temperature ◽  
Cdc2 Kinase ◽  
Synthetic Lethal ◽  
Cycle Arrest ◽  
Novel Protein

Abstract In the fission yeast Schizosaccharomyces pombe, as in other eukaryotic cells, Cdc2/cyclin B complex is the key regulator of mitosis. Perhaps the most important regulation of Cdc2 is the inhibitory phosphorylation of tyrosine-15 that is catalyzed by Wee1 and Mik1. Cdc25 and Pyp3 phosphatases dephosphorylate tyrosine-15 and activate Cdc2. To isolate novel activators of Cdc2 kinase, we screened synthetic lethal mutants in a cdc25-22 background at the permissive temperature (25°). One of the genes, slm9, encodes a novel protein of 807 amino acids. Slm9 is most similar to Hir2, the histone gene regulator in budding yeast. Slm9 protein level is constant and Slm9 is localized to the nucleus throughout the cell cycle. The slm9 disruptant is delayed at the G2-M transition as indicated by cell elongation and analysis of DNA content. Inactivation of Wee1 fully suppressed the cell elongation phenotype caused by the slm9 mutation. The slm9 mutant is defective in recovery from G1 arrest after nitrogen starvation. The slm9 mutant is also UV sensitive, showing a defect in recovery from the cell cycle arrest after UV irradiation.

scholarly journals A Yeast taf17 Mutant Requires the Swi6 Transcriptional Activator for Viability and Shows Defects in Cell Cycle-Regulated Transcription

Genetics ◽  
2000 ◽  
Vol 154 (4) ◽  
pp. 1561-1576
Author(s):  
Neil Macpherson ◽  
Vivien Measday ◽  
Lynda Moore ◽  
Brenda Andrews
Keyword(s):  
Cell Cycle ◽  
Transcriptional Activation ◽  
Essential Gene ◽  
Temperature Sensitive ◽  
Permissive Temperature ◽  
Synthetic Lethal ◽  
Cycle Arrest ◽  
A Cell ◽  
Allelism Tests ◽  
Complementation Groups

Abstract In Saccharomyces cerevisiae, the Swi6 protein is a component of two transcription factors, SBF and MBF, that promote expression of a large group of genes in the late G1 phase of the cell cycle. Although SBF is required for cell viability, SWI6 is not an essential gene. We performed a synthetic lethal screen to identify genes required for viability in the absence of SWI6 and identified 10 complementation groups of swi6-dependent lethal mutants, designated SLM1 through SLM10. We were most interested in mutants showing a cell cycle arrest phenotype; both slm7-1 swi6Δ and slm8-1 swi6Δ double mutants accumulated as large, unbudded cells with increased 1N DNA content and showed a temperature-sensitive growth arrest in the presence of Swi6. Analysis of the transcript levels of cell cycle-regulated genes in slm7-1 SWI6 mutant strains at the permissive temperature revealed defects in regulation of a subset of cyclin-encoding genes. Complementation and allelism tests showed that SLM7 is allelic with the TAF17 gene, which encodes a histone-like component of the general transcription factor TFIID and the SAGA histone acetyltransferase complex. Sequencing showed that the slm7-1 allele of TAF17 is predicted to encode a version of Taf17 that is truncated within a highly conserved region. The cell cycle and transcriptional defects caused by taf17slm7-1 are consistent with the role of TAFIIs as modulators of transcriptional activation and may reflect a role for TAF17 in regulating activation by SBF and MBF.

scholarly journals Saccharomyces cerevisiae Mpt5p interacts with Sst2p and plays roles in pheromone sensitivity and recovery from pheromone arrest.

1997 ◽  
Vol 17 (6) ◽  
pp. 3429-3439 ◽  
Author(s):  
T Chen ◽  
J Kurjan
Keyword(s):  
Mitogen Activated Protein Kinase ◽  
Yeast Cells ◽  
Temperature Sensitive ◽  
G1 Arrest ◽  
Pheromone Response ◽  
Gtpase Activating Proteins ◽  
Mitogen Activated Protein ◽  
Response And Recovery ◽  
Growth Phenotype ◽  
Two Hybrid

SST2 plays an important role in the sensitivity of yeast cells to pheromone and in recovery from pheromone-induced G1 arrest. Recently, a family of Sst2p homologs that act as GTPase-activating proteins (GAPs) for G alpha subunits has been identified. We have identified an interaction between Sst2p and the previously identified Mpt5p by using the two-hybrid system. Loss of Mpt5p function resulted in a temperature-sensitive growth phenotype, an increase in pheromone sensitivity, and a defect in recovery from pheromone-induced G1 arrest, although the effects on pheromone response and recovery were mild in comparison to those of sst2 mutants. Overexpression of either Sst2p or Mpt5p promoted recovery from G1 arrest. Promotion of recovery by overexpression of Mpt5p required Sst2p, but the effect of overexpression of Sst2p was only partially dependent on Mpt5p. Mpt5p was also found to interact with the mitogen-activated protein kinase homologs Fus3p and Kss1p, and an mpt5 mutation was able to suppress the pheromone arrest and mating defects of a fus3 mutant. Because either mpt5 or cln3 mutations suppressed the fus3 phenotypes, interactions of Mpt5p with the G1 cyclins and Cdc28p were tested. An interaction between Mpt5p and Cdc28p was detected. We discuss these results with respect to a model in which Sst2p plays a role in pheromone sensitivity and recovery that acts through Mpt5p in addition to a role as a G alpha GAP suggested by the analysis of the Sst2p homologs.

scholarly journals Requirement for TAFII250 Acetyltransferase Activity in Cell Cycle Progression

2000 ◽  
Vol 20 (4) ◽  
pp. 1134-1139 ◽  
Author(s):  
Elizabeth L. Dunphy ◽  
Theron Johnson ◽  
Scott S. Auerbach ◽  
Edith H. Wang
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Progression ◽  
Temperature Sensitive ◽  
Cycle Progression ◽  
Acetyltransferase Activity ◽  
Cycle Arrest ◽  
Protein Encoding ◽  
Acetyltransferase Domain ◽  
Mutant Cells

ABSTRACT The TATA-binding protein (TBP)-associated factor TAFII250 is the largest component of the basal transcription factor IID (TFIID). A missense mutation that maps to the acetyltransferase domain of TAFII250 induces the temperature-sensitive (ts) mutant hamster cell lines ts13 and tsBN462 to arrest in late G1. At the nonpermissive temperature (39.5°C), transcription from only a subset of protein encoding genes, including the G1 cyclins, is dramatically reduced in the mutant cells. Here we demonstrate that the ability of the ts13 allele of TAFII250 to acetylate histones in vitro is temperature sensitive suggesting that this enzymatic activity is compromised at 39.5°C in the mutant cells. Mutagenesis of a putative acetyl coenzyme A binding site produced a TAFII250 protein that displayed significantly reduced histone acetyltransferase activity but retained TBP and TAFII150 binding. Expression of this mutant in ts13 cells was unable to complement the cell cycle arrest or transcriptional defect observed at 39.5°C. These data suggest that TAFII250 acetyltransferase activity is required for cell cycle progression and regulates the expression of essential proliferative control genes.

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