scholarly journals Investigating the mechanism of the Tup1-Cyc8 (Ssn6) Co-Repressor complex in the yeast Saccharomyces cerevisiae

2020 ◽  
Vol 2 (7A) ◽  
Author(s):  
Brenda Lee
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Stress Response ◽  
Target Genes ◽  
Nuclear Protein ◽  
Yeast Saccharomyces Cerevisiae ◽  
Sequence Of Events ◽  
Repressive Chromatin ◽  
Activation Of Transcription ◽  
Independent Functions ◽  
Repressor Complex

The Tup1-Cyc8 (Ssn6) complex is a powerful epigenetic repressor of genes in the yeast Saccharomyces cerevisiae. The highly conserved complex brings about a repressive chromatin structure at regulatory regions of its target genes or prevents the recruitment of factors needed for activation of transcription. A gap in the current understanding is whether each of the subunits contribute differently to repression. The FLO family of genes are repressed by the Tup1-Cyc8 complex, these genes encode the proteins required for flocculation, a stress response in yeast where the cells aggregate, or form flocs, to protect cells within the floc. Interestingly, each mutant strain has a distinct flocculant phenotype. The tup1Δ strain displays large, dense flocs compared to smaller, more dispersed flocs associated with the cyc8Δ strain. RT-qPCR showed that FLO1 is highly de-repressed in the tup1Δ strain whereas it is de-repressed to a significantly lower level in the cyc8Δ strain. Using the Anchor Away (AA) technique, which allows for a nuclear protein to be conditionally sequestered to the cytoplasm, I am investigating differences in the sequence of events at the FLO1 promoter when Tup1p or when Cyc8p is removed from the nucleus. Six hours after Cyc8p is removed from the nucleus transcription of FLO1 almost reaches the maximum transcription seen in the cyc8Δstrain. However, six hours after removing Tup1p the level of transcription of FLO1 is still over ten times lower than the maximum transcription in tup1Δ. This difference indicates that each of the subunits have independent functions within the complex.

RPD3 encodes a second factor required to achieve maximum positive and negative transcriptional states in Saccharomyces cerevisiae

1991 ◽  
Vol 11 (12) ◽  
pp. 6317-6327 ◽  
Author(s):  
M Vidal ◽  
R F Gaber
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Target Genes ◽  
Current Data ◽  
Regulatory Function ◽  
Fourfold Increase ◽  
Recessive Mutations ◽  
Activation Of Transcription ◽  
Transcriptional Regulatory ◽  
Low Levels ◽  
Full Activation

In Saccharomyces cerevisiae, TRK1 and TRK2 encode the high- and low-affinity K+ transporters, respectively. In cells containing a deletion of TRK1, transcription levels of TRK2 are extremely low and are limiting for growth in media containing low levels of K+ (Trk- phenotype). Recessive mutations in RPD1 and RPD3 suppress the TRK2, conferring an approximately fourfold increase in transcription. rpd3 mutations confer pleiotropic phenotypes, including (i) mating defects, (ii) hypersensitivity to cycloheximide, (iii) inability to sporulate as homozygous diploids, and (iv) constitutive derepression of acid phosphatase. RPD3 was cloned and is predicted to encode a 48-kDa protein with no extensive similarity to proteins contained in current data bases. Deletion of RPD3 is not lethal but confers phenotypes identical to those caused by spontaneous mutations. RPD3 is required for both full repression and full activation of transcription of target genes including PHO5, STE6, and TY2. RPD3 is the second gene required for this function, since RPD1 is also required. The effects of mutations in RPD1 and RPD3 are not additive, suggesting that these genes are involved in the same transcriptional regulatory function or pathway.

Insights into Responses to Extreme Environmental Conditions in Humans from Studies on Saccharomyces cerevisiae

2015 ◽  
Vol 65 (6) ◽  
pp. 444
Author(s):  
Ramesh C. Meena ◽  
Amitabha Chakrabarti
Keyword(s):  
Gene Expression ◽  
Saccharomyces Cerevisiae ◽  
Stress Response ◽  
Gene Expression Data ◽  
Molecular Mechanisms ◽  
Multiple Stressors ◽  
Expression Data ◽  
Environmental Stress Response ◽  
Yeast Saccharomyces Cerevisiae ◽  
Pathways Analysis

<p>The versatility of the yeast experimental model has aided in innumerable ways in the understanding of fundamental cellular functions and has also contributed towards the elucidation of molecular mechanisms underlying several pathological conditions in humans. Genome-wide expression, functional, localization and interaction studies on the yeast Saccharomyces cerevisiae exposed to various stressors have made profound contributions towards the understanding of stress response pathways. Analysis of gene expression data from S. cerevisiae cells indicate that the expression of a common set of genes is altered upon exposure to all the stress conditions examined. This common response to multiple stressors is known as the Environmental stress response. Knowledge gained from studies on the yeast model has now become helpful in understanding stress response pathways and associated disease conditions in humans. Cross-species microarray experiments and analysis of data with ever improving computational methods has led to a better comparison of gene expression data between diverse organisms that include yeast and humans.</p>

scholarly journals Role of Heat Shock Transcription Factor in Saccharomyces cerevisiae Oxidative Stress Response

2007 ◽  
Vol 6 (8) ◽  
pp. 1373-1379 ◽  
Author(s):  
Ayako Yamamoto ◽  
Junko Ueda ◽  
Noritaka Yamamoto ◽  
Naoya Hashikawa ◽  
Hiroshi Sakurai
Keyword(s):  
Oxidative Stress ◽  
Saccharomyces Cerevisiae ◽  
Transcription Factor ◽  
Stress Response ◽  
Heat Shock ◽  
Superoxide Anion ◽  
Target Genes ◽  
Oxidative Stress Response ◽  
Heat Shock Transcription Factor ◽  
Negative Regulator

ABSTRACT The heat shock transcription factor Hsf1 of the yeast Saccharomyces cerevisiae regulates the transcription of a set of genes that contain heat shock elements (HSEs) in their promoters and function in diverse cellular processes, including protein folding. Here, we show that Hsf1 activates the transcription of various target genes when cells are treated with oxidizing reagents, including the superoxide anion generators menadione and KO2 and the thiol oxidants diamide and 1-chloro-2,4-dinitrobenzene (CDNB). Similar to heat shock, the oxidizing reagents are potent inducers of both efficient HSE binding and extensive phosphorylation of Hsf1. The inducible phosphorylation of Hsf1 is regulated by the intramolecular domain-domain interactions and affects HSE structure-specific transcription. Unlike the heat shock, diamide, or CDNB response, menadione or KO2 activation of Hsf1 is inhibited by cyclic-AMP-dependent protein kinase (PKA) activity, which negatively regulates the activator functions of other transcriptional regulators implicated in the oxidative stress response. These results demonstrate that Hsf1 is a member of the oxidative stress-responsive activators and that PKA is a general negative regulator in the superoxide anion response.

scholarly journals Synergistic release from glucose repression by mig1 and ssn mutations in Saccharomyces cerevisiae.

Genetics ◽  
1994 ◽  
Vol 137 (1) ◽  
pp. 49-54 ◽  
Author(s):  
L G Vallier ◽  
M Carlson
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Protein Kinase ◽  
Dna Binding ◽  
Glucose Repression ◽  
Binding Protein ◽  
Dna Binding Protein ◽  
Yeast Saccharomyces Cerevisiae ◽  
Suc2 Promoter ◽  
Repressor Complex ◽  
Glucose Availability

Abstract In the yeast Saccharomyces cerevisiae, glucose repression of SUC2 transcription requires the SSN6-TUP1 repressor complex. It has been proposed that the DNA-binding protein MIG1 secures SSN6-TUP1 to the SUC2 promoter. Here we show that a mig1 deletion does not cause nearly as dramatic a loss of repression as ssn6: glucose-grown mig1 mutants display 20-fold lower SUC2 expression than ssn6 mutants. Thus, repression by SSN6-TUP1 is not mediated solely by MIG1, but also involves MIG1-independent mechanisms. We report that mig1 partially restores SUC2 expression in mutants lacking the SNF1 protein kinase and show that mig1 is allelic to ssn1, a mutation selected as a suppressor of snf1. Other SSN genes identified in this selection were therefore candidates for a role in repression of SUC2. We show that mig1 acts synergistically with ssn2 through ssn5, ssn7, and ssn8 to relieve glucose repression of SUC2 and to suppress the requirement for SNF1. These findings indicate that the SSN proteins contribute to repression of SUC2, and the pleiotropic phenotypes of the ssn mutants suggest global roles in repression. Finally, the regulated SUC2 expression observed in snf1 mig1 mutants indicates that signals regarding glucose availability can be transmitted independently of the SNF1 protein kinase.

Transpositional competence and transcription of endogenous Ty elements in Saccharomyces cerevisiae: implications for regulation of transposition

1988 ◽  
Vol 8 (9) ◽  
pp. 3571-3581 ◽  
Author(s):  
M J Curcio ◽  
N J Sanders ◽  
D J Garfinkel
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Target Genes ◽  
Yeast Cells ◽  
Yeast Genome ◽  
Yeast Saccharomyces Cerevisiae ◽  
Transposition Frequency ◽  
Ty Elements ◽  
Gal1 Promoter ◽  
Per Gene ◽  
Posttranscriptional Level

Transposition of Ty elements in the yeast Saccharomyces cerevisiae occurs through an RNA intermediate. Although Ty RNA accounts for 5 to 10% of the total polyadenylated RNA in a haploid cell, the transposition frequency is only 10(-7) to 10(-8) per gene. To determine whether Ty elements native to the yeast genome are transpositionally competent, two elements were fused to the GAL1 promoter and tested for their ability to transpose. These native elements, Ty1-588 and Ty2-117, transposed at high levels when the GAL1 promoter was induced. Three Ty's identified as spontaneous transpositions in specific target genes were also tested. Of these three, Ty2-917 and the previously characterized element Ty1-H3 were shown to be transpositionally competent. The third element, Ty1-H1, was transposition defective. In addition, we marked the chromosomal copy of Ty1-588 with the NEO gene and demonstrated that Ty1-588NEO was actively transcribed in yeast cells. Ty1-588NEO transcription was regulated by the SPT3 and MAT loci in the same manner as that observed for Ty's collectively. These results indicate that the yeast genome contains functional Ty elements. The presence of a transpositionally competent, actively transcribed element suggests that regulation of Ty transposition occurs at a posttranscriptional level.

Tolerance and stress response to ethanol in the yeast Saccharomyces cerevisiae

2009 ◽  
Vol 85 (2) ◽  
pp. 253-263 ◽  
Author(s):  
Junmei Ding ◽  
Xiaowei Huang ◽  
Lemin Zhang ◽  
Na Zhao ◽  
Dongmei Yang ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Stress Response ◽  
Yeast Saccharomyces Cerevisiae

scholarly journals Expression of YAP4 in Saccharomyces cerevisiae under osmotic stress

2004 ◽  
Vol 379 (2) ◽  
pp. 367-374 ◽  
Author(s):  
Tracy NEVITT ◽  
Jorge PEREIRA ◽  
Dulce AZEVEDO ◽  
Paulo GUERREIRO ◽  
Claudina RODRIGUES-POUSADA
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Stress Response ◽  
Osmotic Stress ◽  
Osmotic Shock ◽  
Glycerol Dehydrogenase ◽  
Mrna Levels ◽  
Yeast Saccharomyces Cerevisiae ◽  
Moderate Growth ◽  
Mutant Induction ◽  
Decapping Enzyme

YAP4, a member of the yeast activator protein (YAP) gene family, is induced in response to osmotic shock in the yeast Saccharomyces cerevisiae. The null mutant displays mild and moderate growth sensitivity at 0.4 M and 0.8 M NaCl respectively, a fact that led us to analyse YAP4 mRNA levels in the hog1 (high osmolarity glycerol) mutant. The data obtained show a complete abolition of YAP4 gene expression in this mutant, placing YAP4 under the HOG response pathway. YAP4 overexpression not only suppresses the osmosensitivity phenotype of the yap4 mutant but also relieves that of the hog1 mutant. Induction, under the conditions tested so far, requires the presence of the transcription factor Msn2p, but not of Msn4p, as YAP4 mRNA levels are depleted by at least 75% in the msn2 mutant. This result was further substantiated by the fact that full YAP4 induction requires the two more proximal stress response elements. Furthermore we find that GCY1, encoding a putative glycerol dehydrogenase, GPP2, encoding a NAD-dependent glycerol-3-phosphate phosphatase, and DCS2, a homologue to a decapping enzyme, have decreased mRNA levels in the yap4-deleted strain. Our data point to a possible, as yet not entirely understood, role of the YAP4 in osmotic stress response.

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