scholarly journals Steady-state analysis of glucose repression reveals hierarchical expression of proteins under Mig1p control in Saccharomyces cerevisiae

2005 ◽  
Vol 388 (3) ◽  
pp. 843-849 ◽  
Author(s):  
Malkhey VERMA ◽  
Paike J. BHAT ◽  
K. V. VENKATESH
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Steady State ◽  
Glucose Repression ◽  
Transcriptional Response ◽  
Mitogen Activated Protein Kinase ◽  
Critical Feature ◽  
Steady State Analysis ◽  
Mitogen Activated Protein ◽  
Kinase Cascade ◽  
State Analysis

Glucose repression is a global transcriptional regulatory mechanism commonly observed in micro-organisms for the repression of enzymes that are not essential for glucose metabolism. In Saccharomyces cerevisiae, Mig1p, a homologue of Wilms' tumour protein, is a global repressor protein dedicated to glucose repression. Mig1p represses genes either by binding directly to the upstream repression sequence of structural genes or by indirectly repressing a transcriptional activator, such as Gal4p. In addition, some genes are repressed by both of the above mechanisms. This raises a fundamental question regarding the physiological relevance of the varied mechanisms of repression that exist involving Mig1p. We address this issue by comparing two well-known glucose-repression systems, that is, SUC2 and GAL gene expression systems, which encompass all the above three mechanisms. We demonstrate using steady-state analysis that these mechanisms lead to a hierarchical glucose repression profile of different family of genes. This switch over from one carbon source to another is well-calibrated as a function of glucose concentration through this hierarchical transcriptional response. The mechanisms prevailing in this repression system can achieve amplification and sensitivity, as observed in the well-characterized MAPK (mitogen-activated protein kinase) cascade system, albeit through a different structure. A critical feature of repression predicted by our steady-state model for the mutant strain of S. cerevisiae lacking Gal80p agrees well with the data reported here as well as that available in the literature.

scholarly journals Osmotic Stress-Induced Gene Expression in Saccharomyces cerevisiae Requires Msn1p and the Novel Nuclear Factor Hot1p

1999 ◽  
Vol 19 (8) ◽  
pp. 5474-5485 ◽  
Author(s):  
Martijn Rep ◽  
Vladimír Reiser ◽  
Ulrike Gartner ◽  
Johan M. Thevelein ◽  
Stefan Hohmann ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Osmotic Stress ◽  
Transcriptional Response ◽  
Mitogen Activated Protein Kinase ◽  
The Novel ◽  
Hog Pathway ◽  
High Osmolarity ◽  
Nuclear Factors ◽  
Mitogen Activated Protein ◽  
Protective Genes

ABSTRACT After a sudden shift to high osmolarity, Saccharomyces cerevisiae cells respond by transiently inducing the expression of stress-protective genes. Msn2p and Msn4p have been described as two transcription factors that determine the extent of this response. Inmsn2 msn4 mutants, however, many promoters still show a distinct rise in transcriptional activity upon osmotic stress. Here we describe two structurally related nuclear factors, Msn1p and a newly identified protein, Hot1p (for high-osmolarity-induced transcription), which are also involved in osmotic stress-induced transcription.hot1 single mutants are specifically compromised in the transient induction of GPD1 and GPP2, which encode enzymes involved in glycerol biosynthesis, and exhibit delayed glycerol accumulation after stress exposure. Similar to agpd1 mutation, a hot1 defect can rescue cells from inappropriately high HOG pathway activity. In contrast, Hot1p has little influence on the osmotic stress induction of CTT1, where Msn1p appears to play a more prominent role. Cells lacking Msn1p, Msn2p, Msn4p, and Hot1p are almost devoid of the short-term transcriptional response of the genes GPD1,GPP2, CTT1, and HSP12 to osmotic stress. Such cells also show a distinct reduction in the nuclear residence of the mitogen-activated protein kinase Hog1p upon osmotic stress. Thus, Hot1p and Msn1p may define an additional tier of transcriptional regulators that control responses to high-osmolarity stress.

scholarly journals Cooperative Regulation of DOG2, Encoding 2-Deoxyglucose-6-Phosphate Phosphatase, by Snf1 Kinase and the High-Osmolarity Glycerol–Mitogen-Activated Protein Kinase Cascade in Stress Responses of Saccharomyces cerevisiae

2000 ◽  
Vol 182 (18) ◽  
pp. 5121-5126 ◽  
Author(s):  
Yoshiyuki Tsujimoto ◽  
Shingo Izawa ◽  
Yoshiharu Inoue
Keyword(s):  
Oxidative Stress ◽  
Gene Expression ◽  
Saccharomyces Cerevisiae ◽  
Osmotic Stress ◽  
Mitogen Activated Protein Kinase ◽  
High Osmolarity ◽  
High Osmolarity Glycerol ◽  
Mitogen Activated Protein ◽  
Kinase Cascade ◽  
Protein Kinase Cascade

ABSTRACT We screened the genome of Saccharomyces cerevisiae for the genes responsive to oxidative stress by using the lacZtransposon-insertion library. As a result, we found that expression of the DOG2 gene coding for 2-deoxyglucose-6-phosphate phosphatase was induced by oxidative stress. The expression ofDOG2 was also induced by osmotic stress. We found a putative cis element (STRE, a stress response element) in the DOG2 promoter adjacent to a consensus sequence to which the Mig1p repressor is known to bind. The basal levels ofDOG2 gene expression were increased in amig1Δ mutant, while the derepression of DOG2was not observed in a snf1Δ mutant under glucose-deprived conditions. Induction of the DOG2 gene expression by osmotic stress was observed in any of the three disruptantspbs2Δ, hog1Δ, and snf1Δ. However, the osmotic induction was completely abolished in both thesnf1Δ pbs2Δ mutant and the snf1Δ hog1Δ mutant. Additionally, these single mutants as well as double mutants failed to induce DOG2 expression by oxidative stress. These results suggest that Snf1p kinase and the high-osmolarity glycerol–mitogen-activated protein kinase cascade are likely to be involved in the signaling pathway of oxidative stress and osmotic stress in regulation of DOG2.

scholarly journals Coordination of the mating and cell integrity mitogen-activated protein kinase pathways in Saccharomyces cerevisiae.

1997 ◽  
Vol 17 (11) ◽  
pp. 6517-6525 ◽  
Author(s):  
B M Buehrer ◽  
B Errede
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Map Kinase ◽  
Mitogen Activated Protein Kinase ◽  
Cell Integrity ◽  
Mating Partner ◽  
Kinase Activation ◽  
Mitogen Activated Protein ◽  
Kinase Cascade ◽  
Mating Pathway ◽  
Transcriptional Output

Mating pheromone stimulates a mitogen-activated protein (MAP) kinase activation pathway in Saccharomyces cerevisiae that induces cells to differentiate and form projections oriented toward the gradient of pheromone secreted by a mating partner. The polarized growth of mating projections involves new cell wall synthesis, a process that relies on activation of the cell integrity MAP kinase, Mpk1. In this report, we show that Mpk1 activation during pheromone induction requires the transcriptional output of the mating pathway and protein synthesis. Consequently, Mpk1 activation occurs subsequent to the activation of the mating pathway MAP kinase cascade. Additionally, Spa2 and Bni1, a formin family member, are two coil-coil-related proteins that are involved in the timing and other aspects of mating projection formation. Both proteins also affect the timing and extent of Mpk1 activation. This correlation suggests that projection formation comprises part of the pheromone-induced signal that coordinates Mpk1 activation with mating differentiation. Stimulation of Mpk1 activity occurs through the cell integrity phosphorylation cascade and depends on Pkc1 and the redundant MAP/Erk kinases (MEKs), Mkk1 and Mkk2. Surprisingly, Mpk1 activation by pheromone was only partially impaired in cells lacking the MEK kinase Bck1. This Bck1-independent mechanism reveals the existence of an alternative activator of Mkk1/Mkk2 in some strain backgrounds that at least functions under pheromone-induced conditions.

Cell extensions in pkc1 mutants of Saccharomyces cerevisiae

1999 ◽  
Vol 45 (1) ◽  
pp. 38-44 ◽  
Author(s):  
M Azuma ◽  
S Torii ◽  
J Kato ◽  
H Ooshima
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Wall ◽  
Isoamyl Alcohol ◽  
Mitogen Activated Protein Kinase ◽  
Cell Integrity ◽  
Actin Cable ◽  
Mitogen Activated Protein ◽  
Kinase Cascade ◽  
Cell Surface Structure ◽  
Protein Kinase Cascade

To obtain information on cell wall synthesis and its relationship to morphology, we examined the induction of cell extensions of yeast upon the addition of isoamyl alcohol in osmotically fragile mutants that had mutations in genes related to the cell integrity pathway through activation of the mitogen-activated protein kinase cascade. We found that isoamyl alcohol induces cell extensions in pkc1 deletion mutants but not in mutants with mutations in genes positioned downstream or upstream of the PKC1 gene. These results suggest that Pkc1p functions not only in the integrity pathway but also in the induction. We characterized the elongated cells; many had two or more nuclei. We found no difference in cell surface structure between round and elongated cells from the results of chitin staining and cell wall extraction. Actin cytoskeleton was organized in elongated cells, as well as round cells. Cytochalasin D (0.08 mg/mL) inhibited the formation of actin cable but did not affect the induction of cell extensions.Key words: Saccharomyces cerevisiae, pkc1, isoamyl alcohol, cell extension.

scholarly journals Mitogen-Activated Protein Kinase Hog1 Is Essential for the Response to Arsenite in Saccharomyces cerevisiae

2006 ◽  
Vol 5 (10) ◽  
pp. 1826-1830 ◽  
Author(s):  
Jael Sotelo ◽  
Miguel A. Rodríguez-Gabriel
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Protein Kinase ◽  
Budding Yeast ◽  
Transcriptional Response ◽  
Mitogen Activated Protein Kinase ◽  
Mitogen Activated Protein ◽  
First Time

ABSTRACT Here we describe, for the first time, that budding yeast mitogen-activated protein kinase Hog1 and its upstream activators Pbs2 and Ssk1 are essential for the response to arsenite. Hog1 is rapidly phosphorylated in response to arsenite and triggers a transcriptional response that involves the upregulation of genes essential for arsenite detoxification.

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