scholarly journals The REG1 Gene Product Is Required for Repression of INO1 and Other Inositol-Sensitive Upstream Activating Sequence-Containing Genes of Yeast

Genetics ◽  
1999 ◽  
Vol 152 (1) ◽  
pp. 89-100 ◽  
Author(s):  
Qian Ouyang ◽  
Monica Ruiz-Noriega ◽  
Susan A Henry
Keyword(s):  
Regulatory Protein ◽  
Deletion Mutation ◽  
Negative Regulator ◽  
Regulatory Subunit ◽  
Bhlh Protein ◽  
Gene Products ◽  
Glucose Response ◽  
Upstream Activating Sequence ◽  
Missense Mutant ◽  
Single Base Pair

Abstract A search was conducted for suppressors of the inositol auxotrophic phenotype of the ino4-8 mutant of yeast. The ino4-8 mutation is a single base pair change that results in substitution of lysine for glutamic acid at position 79 in the bHLH domain of the yeast regulatory protein, Ino4p. Ino4p dimerizes with a second bHLH protein, Ino2p, to form a complex that binds to the promoter of the INO1 gene, activating transcription. Of 31 recessive suppressors of ino4-8 isolated, 29 proved to be alleles of a single locus, identified as REG1, which encodes a regulatory subunit of a protein phosphatase involved in the glucose response pathway. The suppressor mutation, sia1-1, identified as an allele of REG1, caused constitutive INO1 expression and was capable of suppressing the inositol auxotrophy of a second ino4 missense mutant, ino4-26, as well as ino2-419, a missense mutation of INO2. The suppressors analyzed were unable to suppress ino2 and ino4 null mutations, but the reg1 deletion mutation could suppress ino4-8. A deletion mutation in the OPI1 negative regulator was incapable of suppressing ino4-8. The relative roles of the OPI1 and REG1 gene products in control of INO1 expression are discussed.

Dimerization through the helix-loop-helix motif enhances phosphorylation of the transcription activation domains of myogenin

1994 ◽  
Vol 14 (9) ◽  
pp. 6232-6243
Author(s):  
J Zhou ◽  
E N Olson
Keyword(s):  
Transcriptional Activity ◽  
Transcription Activation ◽  
Bhlh Protein ◽  
Specific Gene ◽  
Phosphorylation Sites ◽  
Gene Products ◽  
Activation Domains ◽  
Helix Loop Helix ◽  
Carboxyl Terminal ◽  
Bhlh Proteins

The muscle-specific basic helix-loop-helix (bHLH) protein myogenin activates muscle transcription by binding to target sequences in muscle-specific promoters and enhancers as a heterodimer with ubiquitous bHLH proteins, such as the E2A gene products E12 and E47. We show that dimerization with E2A products potentiates phosphorylation of myogenin at sites within its amino- and carboxyl-terminal transcription activation domains. Phosphorylation of myogenin at these sites was mediated by the bHLH region of E2A products and was dependent on dimerization but not on DNA binding. Mutations of the dimerization-dependent phosphorylation sites resulted in enhanced transcriptional activity of myogenin, suggesting that their phosphorylation diminishes myogenin's transcriptional activity. The ability of E2A products to potentiate myogenin phosphorylation suggests that dimerization induces a conformational change in myogenin that unmasks otherwise cryptic phosphorylation sites or that E2A proteins recruit a kinase for which myogenin is a substrate. That phosphorylation of these dimerization-dependent sites diminished myogenin's transcriptional activity suggests that these sites are targets for a kinase that interferes with muscle-specific gene expression.

Production of the CYS3 regulator, a bZIP DNA-binding protein, is sufficient to induce sulfur gene expression in Neurospora crassa

1992 ◽  
Vol 12 (4) ◽  
pp. 1568-1577
Author(s):  
J V Paietta
Keyword(s):  
Gene Expression ◽  
Neurospora Crassa ◽  
Structural Gene ◽  
Control Point ◽  
Regulatory Protein ◽  
Negative Regulator ◽  
Temperature Sensitive ◽  
Cys3 Protein

The cys-3+ gene of Neurospora crassa encodes a bZIP (basic region-leucine zipper) regulatory protein that is essential for sulfur structural gene expression (e.g., ars-1+). Nuclear transcription assays confirmed that cys-3+ was under sulfur-regulated transcriptional control and that cys-3+ transcription was constitutive in sulfur controller (scon)-negative regulator mutants. Given these results, I have tested whether expression of cys-3+ under high-sulfur (repressing) conditions was sufficient to induce sulfur gene expression. The N. crassa beta-tubulin (tub) promoter was fused to the cys-3+ coding segment and used to transform a cys-3 deletion mutant. Function of the tub::cys-3 fusion in homokaryotic transformants grown under high-sulfur conditions was confirmed by Northern (RNA) and Western immunoblot analysis. The tub::cys-3 transformants showed arylsulfatase gene expression under normally repressing high-sulfur conditions. A tub::cys-3ts fusion encoding a temperature-sensitive CYS3 protein was used to confirm that the induced structural gene expression was due to CYS3 protein function. Constitutive CYS3 production did not induce scon-2+ expression under repressing conditions. In addition, a cys-3 promoter fusion to lacZ showed that CYS3 production was sufficient to induce its own expression and provides in vivo evidence for autoregulation. Finally, an apparent inhibitory effect observed with a strain carrying a point mutation at the cys-3 locus was examined by in vitro heterodimerization studies. These results support an interpretation of CYS3 as a transcriptional activator whose regulation is a crucial control point in the signal response pathway triggered by sulfur limitation.

scholarly journals Characterization of the Noncanonical Regulatory and Transporter Genes in Atratumycin Biosynthesis and Production in a Heterologous Host

Marine Drugs ◽  
2019 ◽  
Vol 17 (10) ◽  
pp. 560 ◽  
Author(s):  
Zhijie Yang ◽  
Xin Wei ◽  
Jianqiao He ◽  
Changli Sun ◽  
Jianhua Ju ◽  
...  
Keyword(s):  
Gene Cluster ◽  
Streptomyces Coelicolor ◽  
Regulatory Gene ◽  
Regulatory Protein ◽  
Biosynthetic Gene Cluster ◽  
Negative Regulator ◽  
Over Expression ◽  
Lead Compounds ◽  
Mycobacteria Tuberculosis ◽  
Abc Transporter Genes

Atratumycin is a cyclodepsipeptide with activity against Mycobacteria tuberculosis isolated from deep-sea derived Streptomyces atratus SCSIO ZH16NS-80S. Analysis of the atratumycin biosynthetic gene cluster (atr) revealed that its biosynthesis is regulated by multiple factors, including two LuxR regulatory genes (atr1 and atr2), two ABC transporter genes (atr29 and atr30) and one Streptomyces antibiotic regulatory gene (atr32). In this work, three regulatory and two transporter genes were unambiguously determined to provide positive, negative and self-protective roles during biosynthesis of atratumycin through bioinformatic analyses, gene inactivations and trans-complementation studies. Notably, an unusual Streptomyces antibiotic regulatory protein Atr32 was characterized as a negative regulator; the function of Atr32 is distinct from previous studies. Five over-expression mutant strains were constructed by rational application of the regulatory and transporter genes; the resulting strains produced significantly improved titers of atratumycin that were ca. 1.7–2.3 fold greater than wild-type (WT) producer. Furthermore, the atratumycin gene cluster was successfully expressed in Streptomyces coelicolor M1154, thus paving the way for the transfer and recombination of large DNA fragments. Overall, this finding sets the stage for understanding the unique biosynthesis of pharmaceutically important atratumycin and lays the foundation for generating anti-tuberculosis lead compounds possessing novel structures.

scholarly journals Nerve growth factor regulates the expression and activity of p33cdk2 and p34cdc2 kinases in PC12 pheochromocytoma cells.

1994 ◽  
Vol 5 (11) ◽  
pp. 1225-1241 ◽  
Author(s):  
K J Buchkovich ◽  
E B Ziff
Keyword(s):  
Transcription Factor ◽  
Nerve Growth Factor ◽  
Growth Factor ◽  
Cell Cycle Progression ◽  
Negative Regulator ◽  
Regulatory Subunit ◽  
Nerve Growth ◽  
Cyclin Dependent Kinases ◽  
Cell Cycling ◽  
Pc12 Differentiation

In the absence of serum, nerve growth factor (NGF) promotes the survival and differentiation of the PC12 pheochromocytoma cell line. In the presence of serum, NGF acts primarily as a differentiation factor and negative regulator of cell cycling. To investigate NGF control of cell cycling, we have analyzed the regulation of cyclin dependent kinases during PC12 cell differentiation. NGF treatment leads to a reduction in the steady-state protein levels of p33cdk2 and p34cdc2, two key regulators of cell cycle progression. The decrease in p33cdk2 and p34cdc2 coincides with a decrease in the enzymatic activity of cyclinA-p34cdc2, cyclinB-p34cdc2, cyclinE-p33cdk2, and cyclinA-p33cdk2 kinases. The decline in p33cdk2 and p34cdc2 kinase activity in response to NGF is accelerated in cells that over-express the p140trk NGF receptor, suggesting that the timing of the down- regulation is dependent on the level of p140trk and the strength of the NGF signal. The level of cyclin A, a regulatory subunit of p33cdk2 and p34cdc2, is relatively constant during PC12 differentiation. Nevertheless, the DNA binding activity of the cyclinA-associated transcription factor E2F/DP decreases. Thus, NGF down-regulates the activity of cyclin dependent kinases and cyclin-transcription factor complexes during PC12 differentiation.

Repair of single base-pair transversion mismatches of Escherichia coli in vitro: correction of certain A/G mismatches is independent of dam methylation and host mutHLS gene functions.

Genetics ◽  
1988 ◽  
Vol 118 (4) ◽  
pp. 593-600 ◽  
Author(s):  
A L Lu ◽  
D Y Chang
Keyword(s):  
Mismatch Repair ◽  
Base Pair ◽  
Repair System ◽  
Gene Products ◽  
Dam Methylation ◽  
Gene Functions ◽  
Mismatch Repair System ◽  
Single Base Pair ◽  
Repair Pathways

Abstract Six different base-pair transversion mismatches are repaired with different efficiencies in an in vitro mismatch repair system. In particular, the T/T and C/C mismatches appear to be less efficiently repaired than the A/A and G/G mismatches. Four A/G and four C/T mismatches at different positions are repaired to different extents. One of the A/G mismatches is repaired equally efficiently when DNA heteroduplexes are fully methylated or hemi-methylated at the d(GATC) sequences. This type of mismatch repair appears to be unidirectional with A to C conversion by acting at A/G mispairs to restore the C/G pairs. This methylation-independent correction is not controlled by the mutH, mutL, mutS, uvrE, uvrB, phr, recA, recF, and recJ gene products. The independence of the transversion mismatch repair of these genes and methylation distinguishes this from the known mismatch repair pathways.

scholarly journals The Role of Cdc55 in the Spindle Checkpoint Is through Regulation of Mitotic Exit in Saccharomyces cerevisiae

2006 ◽  
Vol 17 (2) ◽  
pp. 658-666 ◽  
Author(s):  
Christopher M. Yellman ◽  
Daniel J. Burke
Keyword(s):  
Sister Chromatid ◽  
Spindle Checkpoint ◽  
Sister Chromatid Cohesion ◽  
Mitotic Exit ◽  
Negative Regulator ◽  
Regulatory Subunit ◽  
Checkpoint Activation ◽  
Chromatid Cohesion ◽  
Phosphatase 2A

Cdc55, a B-type regulatory subunit of protein phosphatase 2A, has been implicated in mitotic spindle checkpoint activity and maintenance of sister chromatid cohesion during metaphase. The spindle checkpoint is composed of two independent pathways, one leading to inhibition of the metaphase-to-anaphase transition by checkpoint proteins, including Mad2, and the other to inhibition of mitotic exit by Bub2. We show that Cdc55 is a negative regulator of mitotic exit. A cdc55 mutant, like a bub2 mutant, prematurely releases Cdc14 phosphatase from the nucleolus during spindle checkpoint activation, and premature exit from mitosis indirectly leads to loss of sister chromatid cohesion and inviability in nocodazole. The role of Cdc55 is separable from Bub2 and inhibits release of Cdc14 through a mechanism independent of the known negative regulators of mitotic exit. Epistasis experiments indicate Cdc55 acts either downstream or independent of the mitotic exit network kinase Cdc15. Interestingly, the B-type cyclin Clb2 is partially stable during premature activation of mitotic exit in a cdc55 mutant, indicating mitotic exit is incomplete.

scholarly journals Dimerization through the helix-loop-helix motif enhances phosphorylation of the transcription activation domains of myogenin.

1994 ◽  
Vol 14 (9) ◽  
pp. 6232-6243 ◽  
Author(s):  
J Zhou ◽  
E N Olson
Keyword(s):  
Transcriptional Activity ◽  
Transcription Activation ◽  
Bhlh Protein ◽  
Specific Gene ◽  
Phosphorylation Sites ◽  
Gene Products ◽  
Activation Domains ◽  
Helix Loop Helix ◽  
Carboxyl Terminal ◽  
Bhlh Proteins

The muscle-specific basic helix-loop-helix (bHLH) protein myogenin activates muscle transcription by binding to target sequences in muscle-specific promoters and enhancers as a heterodimer with ubiquitous bHLH proteins, such as the E2A gene products E12 and E47. We show that dimerization with E2A products potentiates phosphorylation of myogenin at sites within its amino- and carboxyl-terminal transcription activation domains. Phosphorylation of myogenin at these sites was mediated by the bHLH region of E2A products and was dependent on dimerization but not on DNA binding. Mutations of the dimerization-dependent phosphorylation sites resulted in enhanced transcriptional activity of myogenin, suggesting that their phosphorylation diminishes myogenin's transcriptional activity. The ability of E2A products to potentiate myogenin phosphorylation suggests that dimerization induces a conformational change in myogenin that unmasks otherwise cryptic phosphorylation sites or that E2A proteins recruit a kinase for which myogenin is a substrate. That phosphorylation of these dimerization-dependent sites diminished myogenin's transcriptional activity suggests that these sites are targets for a kinase that interferes with muscle-specific gene expression.

scholarly journals Toxin, toxin-coregulated pili, and the toxR regulon are essential for Vibrio cholerae pathogenesis in humans.

1988 ◽  
Vol 168 (4) ◽  
pp. 1487-1492 ◽  
Author(s):  
D A Herrington ◽  
R H Hall ◽  
G Losonsky ◽  
J J Mekalanos ◽  
R K Taylor ◽  
...  
Keyword(s):  
Cholera Toxin ◽  
Regulatory Protein ◽  
Deletion Mutation ◽  
Intestinal Colonization ◽  
Gene Encoding ◽  
Disease Symptoms ◽  
Mutant Strains ◽  
A Subunit ◽  
First Time

Isogenic mutant strains of V. cholerae O1 lacking elements of a genetic regulon controlled by toxR and implicated in virulence were tested in volunteers. A deletion mutation in ctxA, the gene encoding the A subunit of cholera toxin, markedly attenuated disease symptoms without affecting intestinal colonization. Deletion of toxR, the gene encoding the cholera toxin-positive regulatory protein resulted in a diminution in colonizing capacity. A deletion mutation in tcpA, encoding the major subunit of the toxin coregulated pilus (regulated by toxR), abolished the colonizing capacity of this strain. These results show for the first time the role of a specific pilus structure in colonization of the human intestine by V. cholerae O1 and exemplify the significance of a genetic regulon in pathogenesis.

Phosphoinositide 3-kinase is activated by MUC1 but not responsible for MUC1-induced suppression of Toll-like receptor 5 signaling

2007 ◽  
Vol 293 (3) ◽  
pp. L686-L692 ◽  
Author(s):  
Kosuke Kato ◽  
Wenju Lu ◽  
Hirofumi Kai ◽  
K. Chul Kim
Keyword(s):  
Cross Talk ◽  
Negative Regulator ◽  
Regulatory Subunit ◽  
Binding Motif ◽  
Toll Like Receptor ◽  
Akt Phosphorylation ◽  
Phosphoinositide 3 Kinase ◽  
Toll Like Receptor 5

MUC1 is a membrane-tethered mucin-like glycoprotein expressed on the surface of various mucosal epithelial cells as well as hematopoietic cells. Recently, we showed that MUC1 suppresses flagellin-induced Toll-like receptor (TLR) 5 signaling both in vivo and in vitro through cross talk with TLR5. In this study, we determined whether phosphoinositide 3-kinase (PI3K), a negative regulator of TLR5 signaling, is involved in the cross talk between MUC1 and TLR5 using various genetically modified epithelial cell lines. Our results showed 1) activation of MUC1 induced recruitment of the PI3K regulatory subunit p85 to the MUC1 cytoplasmic tail (CT) as well as Akt phosphorylation, 2) MUC1-induced Akt phosphorylation required the presence of Tyr20 within the PI3K binding motif of the MUC1 CT, and 3) mutation of Tyr20 or pharmacological inhibition of PI3K activation failed to block MUC1-induced suppression of TLR5 signaling. We conclude that whereas PI3K is downstream of MUC1 activation and negatively regulates TLR5 signaling, it is not responsible for MUC1-induced suppression of TLR5 signaling.

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