scholarly journals Rgt1, a glucose sensing transcription factor, is required for transcriptional repression of the HXK2 gene in Saccharomyces cerevisiae

2005 ◽  
Vol 388 (2) ◽  
pp. 697-703 ◽  
Author(s):  
Aaron PALOMINO ◽  
Pilar HERRERO ◽  
Fernando MORENO
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Transcription Factor ◽  
Transcriptional Repression ◽  
Glucose Repression ◽  
Fold Increase ◽  
Glucose Sensing ◽  
Start Codon ◽  
Dependent Manner ◽  
Gene Encoding ◽  
Regulatory Functions

Expression of HXK2, a gene encoding a Saccharomyces cerevisiae bifunctional protein with catalytic and regulatory functions, is controlled by glucose availability, being activated in the presence of glucose and inhibited when the levels of the sugar are low. In the present study, we identified Rgt1 as a transcription factor that, together with the Med8 protein, is essential for repression of the HXK2 gene in the absence of glucose. Rgt1 represses HXK2 expression by binding specifically to the motif (CGGAAAA) located at −395 bp relative to the ATG translation start codon in the HXK2 promoter. Disruption of the RGT1 gene causes an 18-fold increase in the level of HXK2 transcript in the absence of glucose. Rgt1 binds to the RGT1 element of HXK2 promoter in a glucose-dependent manner, and the repression of target gene depends on binding of Rgt1 to DNA. The physiological significance of the connection between two glucose-signalling pathways, the Snf3/Rgt2 that causes glucose induction and the Mig1/Hxk2 that causes glucose repression, was also analysed.

scholarly journals Multicopy FZF1 (SUL1) Suppresses the Sulfite Sensitivity but Not the Glucose Derepression or Aberrant Cell Morphology of a grr1 Mutant of Saccharomyces cerevisiae

Genetics ◽  
1996 ◽  
Vol 144 (2) ◽  
pp. 511-521 ◽  
Author(s):  
Dorina Avram ◽  
Alan T Bakalinsky
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Transcription Factor ◽  
Glucose Metabolism ◽  
Cell Morphology ◽  
Glucose Repression ◽  
Carbon Sources ◽  
Single Copy ◽  
Aberrant Cell ◽  
Growth Defects ◽  
Putative Transcription Factor

Abstract An ssu2 mutation in Sacccharomyces cermisiae, previously shown to cause sulfite sensitivity, was found to be allelic to GRR1, a gene previously implicated in glucose repression. The suppressor rgt1, which suppresses the growth defects of grr1 strains on glucose, did not fully suppress the sensitivity on glucose or nonglucose carbon sources, indicating that it is not strictly linked to a defect in glucose metabolism. Because the Cln1 protein was previously shown to be elevated in grr1 mutants, the effect of CLN1 overexpression on sulfite sensitivity was investigated. Overexpression in GRR1 cells resulted in sulfite sensitivity, suggesting a connection between CLN1 and sulfite metabolism. Multicopy FZF1, a putative transcription factor, was found to suppress the sulfite sensitive phenotype of grr1 strains, but not the glucose derepression or aberrant cell morphology. Multicopy FZF1 was also found to suppress the sensitivity of a number of other unrelated sulfite-sensitive mutants, but not that of ssu1 or met20, implying that FZF1 may act through Ssulp and Met20p. Disruption of FZF1 resulted in sulfite sensitivity when the construct was introduced in single copy at the FZF1 locus in a GRR1 strain, providing evidence that FZF1 is involved in sulfite metabolism.

scholarly journals Differential activation mechanisms of two isoforms of Gcr1 transcription factor generated from spliced and un-spliced transcripts in Saccharomyces cerevisiae

2020 ◽  
Author(s):  
Seungwoo Cha ◽  
Chang Pyo Hong ◽  
Hyun Ah Kang ◽  
Ji-Sook Hahn
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Transcription Factor ◽  
Target Genes ◽  
Gene Encoding ◽  
Metabolic Switch ◽  
Differential Activation ◽  
N Terminus ◽  
Activation Mechanisms ◽  
In Trans ◽  
Separate Activation

Abstract Gcr1, an important transcription factor for glycolytic genes in Saccharomyces cerevisiae, was recently revealed to have two isoforms, Gcr1U and Gcr1S, produced from un-spliced and spliced transcripts, respectively. In this study, by generating strains expressing only Gcr1U or Gcr1S using the CRISPR/Cas9 system, we elucidate differential activation mechanisms of these two isoforms. The Gcr1U monomer forms an active complex with its coactivator Gcr2 homodimer, whereas Gcr1S acts as a homodimer without Gcr2. The USS domain, 55 residues at the N-terminus existing only in Gcr1U, inhibits dimerization of Gcr1U and even acts in trans to inhibit Gcr1S dimerization. The Gcr1S monomer inhibits the metabolic switch from fermentation to respiration by directly binding to the ALD4 promoter, which can be restored by overexpression of the ALD4 gene, encoding a mitochondrial aldehyde dehydrogenase required for ethanol utilization. Gcr1U and Gcr1S regulate almost the same target genes, but show unique activities depending on growth phase, suggesting that these isoforms play differential roles through separate activation mechanisms depending on environmental conditions.

Control of mRNA turnover as a mechanism of glucose repression in Saccharomyces cerevisiae

1992 ◽  
Vol 12 (7) ◽  
pp. 2941-2948
Author(s):  
A Lombardo ◽  
G P Cereghino ◽  
I E Scheffler
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Succinate Dehydrogenase ◽  
Half Life ◽  
Glucose Repression ◽  
Promoter Sequence ◽  
Regulatory Elements ◽  
Mrna Levels ◽  
Protein Subunit ◽  
Gene Encoding ◽  
Regulatory Complex

We have examined the expression of the gene encoding the iron-protein subunit (Ip) of succinate dehydrogenase in Saccharomyces cerevisiae. The gene had been cloned by us and shown to be subject to glucose regulation (A. Lombardo, K. Carine, and I. E. Scheffler, J. Biol. Chem. 265:10419-10423, 1990). We discovered that a significant part of the regulation of the Ip mRNA levels by glucose involves the regulation of the turnover rate of this mRNA. In the presence of glucose, the half-life appears to be less than 5 min, while in glycerol medium, the half-life is greater than 60 min. The gene is also regulated transcriptionally by glucose. The upstream promoter sequence appeared to have four regulatory elements with consensus sequences shown to be responsible for the interaction with the HAP2/3/4 regulatory complex. A deletion analysis has shown that the two distal elements are redundant. These measurements were carried out by Northern (RNA) analyses of Ip mRNA transcripts as well as by assays of beta-galactosidase activity in cells carrying constructs of the Ip promoter linked to the lacZ coding sequence. These observations on the regulation of mRNA stability were also extended to the mRNA of the flavoprotein subunit of succinate dehydrogenase and in some experiments of iso-1-cytochrome c.

scholarly journals Control of mRNA turnover as a mechanism of glucose repression in Saccharomyces cerevisiae.

1992 ◽  
Vol 12 (7) ◽  
pp. 2941-2948 ◽  
Author(s):  
A Lombardo ◽  
G P Cereghino ◽  
I E Scheffler
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Succinate Dehydrogenase ◽  
Half Life ◽  
Glucose Repression ◽  
Promoter Sequence ◽  
Regulatory Elements ◽  
Mrna Levels ◽  
Protein Subunit ◽  
Gene Encoding ◽  
Regulatory Complex

We have examined the expression of the gene encoding the iron-protein subunit (Ip) of succinate dehydrogenase in Saccharomyces cerevisiae. The gene had been cloned by us and shown to be subject to glucose regulation (A. Lombardo, K. Carine, and I. E. Scheffler, J. Biol. Chem. 265:10419-10423, 1990). We discovered that a significant part of the regulation of the Ip mRNA levels by glucose involves the regulation of the turnover rate of this mRNA. In the presence of glucose, the half-life appears to be less than 5 min, while in glycerol medium, the half-life is greater than 60 min. The gene is also regulated transcriptionally by glucose. The upstream promoter sequence appeared to have four regulatory elements with consensus sequences shown to be responsible for the interaction with the HAP2/3/4 regulatory complex. A deletion analysis has shown that the two distal elements are redundant. These measurements were carried out by Northern (RNA) analyses of Ip mRNA transcripts as well as by assays of beta-galactosidase activity in cells carrying constructs of the Ip promoter linked to the lacZ coding sequence. These observations on the regulation of mRNA stability were also extended to the mRNA of the flavoprotein subunit of succinate dehydrogenase and in some experiments of iso-1-cytochrome c.

scholarly journals Characterization of TUP1, a mediator of glucose repression in Saccharomyces cerevisiae.

1990 ◽  
Vol 10 (12) ◽  
pp. 6500-6511 ◽  
Author(s):  
F E Williams ◽  
R J Trumbly
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Insertional Mutagenesis ◽  
Glucose Repression ◽  
Coding Region ◽  
Gene Encoding ◽  
Reading Frame ◽  
C Terminus ◽  
Single Deletion ◽  
Rna Mapping ◽  
Mutant Phenotypes

The TUP1 and CYC8 (= SSN6) genes of Saccharomyces cerevisiae play a major role in glucose repression. Mutations in either TUP1 or CYC8 eliminate or reduce glucose repression of many repressible genes and induce other phenotypes, including flocculence, failure to sporulate, and sterility of MAT alpha cells. The TUP1 gene was isolated in a screen for genes that regulate mating type (V.L. MacKay, Methods Enzymol. 101:325-343, 1983). We found that a 3.5-kb restriction fragment was sufficient for complete complementation of tup1-100. The gene was further localized by insertional mutagenesis and RNA mapping. Sequence analysis of 2.9 kb of DNA including TUP1 revealed only one long open reading frame which predicts a protein of molecular weight 78,221. The predicted protein is rich in serine, threonine, and glutamine. In the carboxyl region there are six repeats of a pattern of about 43 amino acids. This same pattern of conserved residues is seen in the beta subunit of transducin and the yeast CDC4 gene product. Insertion and deletion mutants are viable, with the same range of phenotypes as for point mutants. Deletions of the 3' end of the coding region produced the same mutant phenotypes as did total deletions, suggesting that the C terminus is critical for TUP1 function. Strains with deletions in both the CYC8 and TUP1 genes are viable, with phenotypes similar to those of strains with a single deletion. A deletion mutation of TUP1 was able to suppress the snf1 mutation block on expression of the SUC2 gene encoding invertase.

scholarly journals The Paired-Domain Transcription Factor Pax8 Binds to the Upstream Enhancer of the Rat Sodium/Iodide Symporter Gene and Participates in Both Thyroid-Specific and Cyclic-AMP-Dependent Transcription

1999 ◽  
Vol 19 (3) ◽  
pp. 2051-2060 ◽  
Author(s):  
Makoto Ohno ◽  
Mariastella Zannini ◽  
Orlie Levy ◽  
Nancy Carrasco ◽  
Roberto di Lauro
Keyword(s):  
Transcription Factor ◽  
Cyclic Amp ◽  
Transcriptional Activation ◽  
Mutational Analysis ◽  
Thyroid Stimulating Hormone ◽  
Dependent Manner ◽  
Sodium Iodide Symporter ◽  
Paired Domain ◽  
Gene Encoding ◽  
Responsive Element

ABSTRACT The gene encoding the Na/I symporter (NIS) is expressed at high levels only in thyroid follicular cells, where its expression is regulated by the thyroid-stimulating hormone via the second messenger, cyclic AMP (cAMP). In this study, we demonstrate the presence of an enhancer that is located between nucleotides −2264 and −2495 in the 5′-flanking region of the NIS gene and that recapitulates the most relevant aspects of NIS regulation. When fused to either its own or a heterologous promoter, the NIS upstream enhancer, which we call NUE, stimulates transcription in a thyroid-specific and cAMP-dependent manner. The activity of NUE depends on the four most relevant sites, identified by mutational analysis. The thyroid-specific transcription factor Pax8 binds at two of these sites. Mutations that interfere with Pax8 binding also decrease transcriptional activity of the NUE. Furthermore, expression of Pax8 in nonthyroid cells results in transcriptional activation of NUE, strongly suggesting that the paired-domain protein Pax8 plays an important role in NUE activity. The NUE responds to cAMP in both protein kinase A-dependent and -independent manners, indicating that this enhancer could represent a novel type of cAMP responsive element. Such a cAMP response requires Pax8 but also depends on the integrity of a cAMP responsive element (CRE)-like sequence, thus suggesting a functional interaction between Pax8 and factors binding at the CRE-like site.

scholarly journals Mutations in RAD6, a yeast gene encoding a ubiquitin-conjugating enzyme, stimulate retrotransposition.

1990 ◽  
Vol 10 (3) ◽  
pp. 1017-1022 ◽  
Author(s):  
S Picologlou ◽  
N Brown ◽  
S W Liebman
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Fold Increase ◽  
Yeast Gene ◽  
Gene Encoding ◽  
Repair Gene ◽  
Dna Repair Gene ◽  
Ubiquitin Conjugating Enzyme ◽  
First Time ◽  
Conjugating Enzyme

The Saccharomyces cerevisiae DNA repair gene RAD6 encodes a ubiquitin-conjugating enzyme which polyubiquitinates histones in vitro. Here we show that mutations in rad6 increase the frequency of transposition of the retrotransposon Ty into the CAN1 and URA3 loci. Using isogenic RAD6 and rad6 strains, we measured a more than 100-fold increase in the spontaneous rate of retrotransposition due to rad6, although there was no increase in the Ty message level. This is the first time that a mutation in a host gene has been shown to result in an increased rate of retrotransposition.

scholarly journals Repressors and Upstream Repressing Sequences of the Stress-Regulated ENA1 Gene in Saccharomyces cerevisiae: bZIP Protein Sko1p Confers HOG-Dependent Osmotic Regulation

1999 ◽  
Vol 19 (1) ◽  
pp. 537-546 ◽  
Author(s):  
Markus Proft ◽  
Ramón Serrano
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Salt Stress ◽  
Osmotic Stress ◽  
Transcriptional Repression ◽  
Glucose Repression ◽  
Osmotic Shock ◽  
Mitogen Activated Protein Kinase ◽  
Deletion Strain ◽  
Binding Motif ◽  
Hog Pathway

ABSTRACT The yeast ENA1/PMR2A gene encodes a cation extrusion ATPase in Saccharomyces cerevisiae which is essential for survival under salt stress conditions. One important mechanism ofENA1 transcriptional regulation is based on repression under normal growth conditions, which is relieved by either osmotic induction or glucose starvation. Analysis of the ENA1promoter revealed a Mig1p-binding motif (−533 to −544) which was characterized as an upstream repressing sequence (URSMIG-ENA1 ) regulated by carbon source. Its function was abolished in a mig1 mig2 double-deletion strain as well as in either ssn6 or tup1 single mutants. A second URS at −502 to −513 is responsible for transcriptional repression regulated by osmotic stress and is similar to mammalian cyclic AMP response elements (CREs) that are recognized by CREB proteins. This URSCRE-ENA1 element requires for its repression function the yeast CREB homolog Sko1p (Acr1p) as well as the integrity of the Ssn6p-Tup1p corepressor complex. When targeted to the GAL1 promoter by fusing with the Gal4p DNA-binding domain, Sko1p acts as an Ssn6/Tup1p-dependent repressor regulated by osmotic stress. A glutathione S -transferase–Sko1 fusion protein binds specifically to the URSCRE-ENA1 element. Furthermore, ahog1 mitogen-activated protein kinase deletion strain could not counteract repression on URSCRE-ENA1 during osmotic shock. The loss of SKO1 completely restoredENA1 expression in a hog1 mutant and partially suppressed the osmotic stress sensitivity, qualifying Sko1p as a downstream effector of the HOG pathway. Our results indicate that different signalling pathways (HOG osmotic pathway and glucose repression pathway) use distinct promoter elements of ENA1(URSCRE-ENA1 and URSMIG-ENA1 ) via specific transcriptional repressors (Sko1p and Mig1/2p) and via the general Ssn6p-Tup1p complex. The physiological importance of the relief from repression during salt stress was also demonstrated by the increased tolerance ofsko1 or ssn6 mutants to Na+ or Li+ stress.

scholarly journals Regulatory Network Connecting Two Glucose Signal Transduction Pathways in Saccharomyces cerevisiae

2004 ◽  
Vol 3 (1) ◽  
pp. 221-231 ◽  
Author(s):  
Aneta Kaniak ◽  
Zhixiong Xue ◽  
Daniel Macool ◽  
Jeong-Ho Kim ◽  
Mark Johnston
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Signal Transduction ◽  
Transcription Factor ◽  
Regulatory Network ◽  
Target Genes ◽  
Glucose Repression ◽  
Signal Transduction Pathways ◽  
Glucose Signaling ◽  
Genes Encoding ◽  
Glucose Induction

ABSTRACT The yeast Saccharomyces cerevisiae senses glucose, its preferred carbon source, through multiple signal transduction pathways. In one pathway, glucose represses the expression of many genes through the Mig1 transcriptional repressor, which is regulated by the Snf1 protein kinase. In another pathway, glucose induces the expression of HXT genes encoding glucose transporters through two glucose sensors on the cell surface that generate an intracellular signal that affects function of the Rgt1 transcription factor. We profiled the yeast transcriptome to determine the range of genes targeted by this second pathway. Candidate target genes were verified by testing for Rgt1 binding to their promoters by chromatin immunoprecipitation and by measuring the regulation of the expression of promoter lacZ fusions. Relatively few genes could be validated as targets of this pathway, suggesting that this pathway is primarily dedicated to regulating the expression of HXT genes. Among the genes regulated by this glucose signaling pathway are several genes involved in the glucose induction and glucose repression pathways. The Snf3/Rgt2-Rgt1 glucose induction pathway contributes to glucose repression by inducing the transcription of MIG2, which encodes a repressor of glucose-repressed genes, and regulates itself by inducing the expression of STD1, which encodes a regulator of the Rgt1 transcription factor. The Snf1-Mig1 glucose repression pathway contributes to glucose induction by repressing the expression of SNF3 and MTH1, which encodes another regulator of Rgt1, and also regulates itself by repressing the transcription of MIG1. Thus, these two glucose signaling pathways are intertwined in a regulatory network that serves to integrate the different glucose signals operating in these two pathways.

Gal80 proteins of Kluyveromyces lactis and Saccharomyces cerevisiae are highly conserved but contribute differently to glucose repression of the galactose regulon

1993 ◽  
Vol 13 (12) ◽  
pp. 7566-7576
Author(s):  
F T Zenke ◽  
W Zachariae ◽  
A Lunkes ◽  
K D Breunig
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Binding Sites ◽  
Glucose Repression ◽  
Kluyveromyces Lactis ◽  
Constitutive Expression ◽  
Indirect Evidence ◽  
Transcriptional Activator ◽  
Negative Regulator ◽  
Gene Encoding ◽  
Fold Induction

We cloned the GAL80 gene encoding the negative regulator of the transcriptional activator Gal4 (Lac9) from the yeast Kluyveromyces lactis. The deduced amino acid sequence of K. lactis GAL80 revealed a strong structural conservation between K. lactis Gal80 and the homologous Saccharomyces cerevisiae protein, with an overall identity of 60% and two conserved blocks with over 80% identical residues. K. lactis gal80 disruption mutants show constitutive expression of the lactose/galactose metabolic genes, confirming that K. lactis Gal80 functions in essentially in the same way as does S. cerevisiae Gal80, blocking activation by the transcriptional activator Lac9 (K. lactis Gal4) in the absence of an inducing sugar. However, in contrast to S. cerevisiae, in which Gal4-dependent activation is strongly inhibited by glucose even in a gal80 mutant, glucose repressibility is almost completely lost in gal80 mutants of K. lactis. Indirect evidence suggests that this difference in phenotype is due to a higher activator concentration in K. lactis which is able to overcome glucose repression. Expression of the K. lactis GAL80 gene is controlled by Lac9. Two high-affinity binding sites in the GAL80 promoter mediate a 70-fold induction by galactose and hence negative autoregulation by Gal80. Gal80 in turn not only controls Lac9 activity but also has a moderate influence on its rate of synthesis. Thus, a feedback control mechanism exists between the positive and negative regulators. By mutating the Lac9 binding sites of the GAL80 promoter, we could show that induction of GAL80 is required to prevent activation of the lactose/galactose regulon in glycerol or glucose plus galactose, whereas the noninduced level of Gal80 is sufficient to completely block Lac9 function in glucose.

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