Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P51532 (transcriptional activator)
 6,546 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Starvation for sulfate results in increased synthesis of several proteins in Escherichia coli. Among these Ssi (sulfate starvation-induced) proteins are the products of the tauABCD genes, which are required for utilization of taurine as sulfur source for growth. In this study, the role of the cbl gene in expression of tauABCD and other ssi genes was investigated. The protein encoded by cbl shows high sequence similarity to CysB, the LysR-type transcriptional activator of the genes involved in cysteine biosynthesis. Strain EC2541, which contains an internal deletion in cbl, was unable to utilize taurine and other aliphatic sulfonates as sulfur sources. Two-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed that many of the Ssi proteins were not synthesized in EC2541. Expression of a translational tauD'-'lacZ fusion required the presence of both cbl and cysB. The interactions of CysB and Cbl with the promoter region of tauABCD were studied by using gel mobility shift experiments and DNase I footprinting. CysB occupied multiple binding sites, whereas Cbl occupied only one site from 112 to 68 bp upstream of the transcription start site. Acetylserine, the inducer of transcription of CysB-regulated genes, stimulated binding of CysB but not of Cbl. Sulfate had no effect on binding of both proteins to the tauABCD promoter region. These results indicate that Cbl is a transcription factor for genes required for sulfonate-sulfur utilization and maybe for other genes whose expression is induced by sulfate starvation.
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PMID:Involvement of CysB and Cbl regulatory proteins in expression of the tauABCD operon and other sulfate starvation-inducible genes in Escherichia coli. 940 Oct 24

Cholesterol sulfate and transglutaminase 1 are essential for the process of keratinization. Cholesterol sulfate is formed during keratinization and activates the eta isoform of protein kinase C. Transglutaminase 1 is a key enzyme for formation of the cornified envelope in terminally differentiated keratinocytes. In this study, we demonstrated that cholesterol sulfate acts as a transcriptional activator of the transglutaminase 1 gene in normal human keratinocytes. Growth of normal human keratinocytes was inhibited by cholesterol sulfate, but not by its parental cholesterol. Treatment of normal human keratinocytes with cholesterol sulfate induced activity of transglutaminase 1 in a dose- and time-dependent manner. Activation of transcription of transglutaminase 1 by cholesterol sulfate was demonstrated by northern blotting analysis, whereas that by cholesterol was not. In order to identify a cholesterol sulfate responsive region in the transglutaminase 1 gene, plasmids were constructed containing a luciferase reporter gene ligated to deletion fragments of the 5' upstream region of the tranglutaminase 1 gene and were transfected into normal human keratinocytes. Transfected cells were treated with cholesterol sulfate, the phorbol ester 12-O-tetradecanoylphorbol-13-acetate and a high concentration of Ca2+. Our results indicate that the responsive element(s) for cholesterol sulfate and phorbol ester is located upstream of the human transglutaminase 1 gene at a position(s) between -819 and -549, whereas the responsive element for Ca2+ is located at a position between -79 and -49.
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PMID:Cholesterol sulfate activates transcription of transglutaminase 1 gene in normal human keratinocytes. 985 23

The transmembrane regulatory protein ToxR is required for expression of virulence factors in the human diarrheal pathogen Vibrio cholerae, including cholera toxin (CT) and the toxin coregulated pilus (TCP). ToxR is necessary for transcription of the gene encoding a second regulatory protein, ToxT, which is the direct transcriptional activator of CT and TCP genes. However, ToxR, independent of ToxT, directly activates and represses transcription of the outer membrane porins OmpU and OmpT, respectively. The genes encoding TCP and CT (and including ToxT) lie on horizontally acquired genetic elements, while the toxR, ompU, and ompT genes are apparently in the ancestral Vibrio chromosome. The contribution of ToxR-dependent modulation of outer membrane porins to cholera pathogenesis has remained unknown. We demonstrate that ToxR mediates enhanced bile resistance in a ToxT-independent manner. In both classical and El Tor biotypes of V. cholerae, a toxR mutant strain has a reduced minimum bactericidal concentration (MBC) of bile, the bile component deoxycholate (DC), and the anionic detergent sodium dodecyl sulfate (SDS) compared to both wild-type and toxT mutant strains. Classical and El Tor toxR mutant strains also exhibit reduced growth rates at subinhibitory concentrations of DC and SDS. Growth of either V. cholerae biotype in subinhibitory concentrations of bile or DC induces increased ToxR-dependent production of a major 38-kDa outer membrane protein, which was confirmed to be OmpU by Western blot. Measurement of transcription of a ompUp-lacZ fusion in both biotypes reveals stimulation (about two- to threefold) of ToxR-dependent ompU transcription by the presence of bile or DC, suggesting that ToxR may respond to the presence of bile. The toxR mutant strains of three additional human intestinal pathogenic Vibrio species, V. mimicus, V. fluvialis, and V. parahaemolyticus, display lower MBCs of bile, DC, and SDS and have altered outer membrane protein profiles compared to the parental wild-type strains. Our results demonstrate a conserved role for ToxR in the modulation of outer membrane proteins and bile resistance of pathogenic Vibrio species and suggest that these ToxR-dependent outer membrane proteins may mediate enhanced resistance to bile. We speculate that ToxR-mediated bile resistance was an early step in the evolution of V. cholerae as an intestinal pathogen.
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PMID:The virulence regulatory protein ToxR mediates enhanced bile resistance in Vibrio cholerae and other pathogenic Vibrio species. 1067 65

The CII protein of the temperate bacteriophage lambda is a transcriptional activator involved in the lysis-lysogeny switch of the phage. It is an unstable protein of 97 amino acids and is known to exist as a tetramer in the native state. The cII gene has been cloned and expressed in Escherichia coli using a T7 promoter based over-expression system. The recombinant CII protein has been purified to homogeneity by ammonium sulfate fractionation followed by two steps of ion-exchange chromatography. The purified protein crystallized at pH 8.2 in hanging-drop vapor diffusion method at 293 K. The crystals diffract to a resolution of 2.8 A and belong to the space group C222 with unit-cell parameters a = 64.10, b = 106.95 and c = 120.16 A.
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PMID:Purification and crystallization of CII: an unstable transcription activator from phage lambda. 1168 8

Genome-wide studies have recently revealed the unexpected complexity of the genetic response to apparently simple physiological changes. Here, we show that when yeast cells are exposed to Cd(2+), most of the sulfur assimilated by the cells is converted into glutathione, a thiol-metabolite essential for detoxification. Cells adapt to this vital metabolite requirement by modifying globally their proteome to reduce the production of abundant sulfur-rich proteins. In particular, some abundant glycolytic enzymes are replaced by sulfur-depleted isozymes. This global change in protein expression allows an overall sulfur amino acid saving of 30%. This proteomic adaptation is essentially regulated at the mRNA level. The main transcriptional activator of the sulfate assimilation pathway, Met4p, plays an essential role in this sulfur-sparing response.
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PMID:Sulfur sparing in the yeast proteome in response to sulfur demand. 1198 64

Expression of the pspABCDE operon of Escherichia coli is induced upon infection by filamentous phage and by many other stress conditions, including defects in protein export. Expression of the operon requires the alternative sigma factor sigma54 and the transcriptional activator PspF. In addition, PspA plays a negative regulatory role, and the integral-membrane proteins PspB and PspC play a positive one. In this study, we investigated whether the suggested protein-protein interactions implicated in this complex regulatory network can indeed be demonstrated. Antisera were raised against PspB, PspC, and PspD, which revealed, in Western blotting experiments, that PspC forms stable sodium dodecyl sulfate-resistant dimers and that the hypothetical pspD gene is indeed expressed in vivo. Fractionation experiments showed that PspD localizes as a peripherally bound inner membrane protein. Cross-linking studies with intact cells revealed specific interactions of PspA with PspB and PspC, but not with PspD. Furthermore, affinity-chromatography suggested that PspB could bind PspA only in the presence of PspC. These data indicate that regulation of the psp operon is mediated via protein-protein interactions.
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PMID:Interactions between phage-shock proteins in Escherichia coli. 1256 86

MSN1 is a putative yeast transcriptional activator involved in chromium (Cr) accumulation. Here we show that overexpression of MSN1 enhances Cr and sulfur accumulation and Cr tolerance in transgenic tobacco. In addition, we found that expression of NtST1 (Nicotiana tabacum sulfate transporter 1) was elevated in MSN1- expressing transgenic tobacco, suggesting that chromate and sulfate are taken up via the sulfate transporter in plants. Supporting this, expression of NtST1 increased levels of Cr and S in Saccharomyces cerevisiae. Our findings suggest that yeast transcriptional activators can be used for developing effective metal remediators, and for improving the nutritional status of plants.
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PMID:Expression of yeast transcriptional activator MSN1 promotes accumulation of chromium and sulfur by enhancing sulfate transporter level in plants. 1636 22

The molecular response of Shewanella oneidensis MR-1 to variations in extracellular pH was investigated based on genomewide gene expression profiling. Microarray analysis revealed that cells elicited both general and specific transcriptome responses when challenged with environmental acid (pH 4) or base (pH 10) conditions over a 60-min period. Global responses included the differential expression of genes functionally linked to amino acid metabolism, transcriptional regulation and signal transduction, transport, cell membrane structure, and oxidative stress protection. Response to acid stress included the elevated expression of genes encoding glycogen biosynthetic enzymes, phosphate transporters, and the RNA polymerase sigma-38 factor (rpoS), whereas the molecular response to alkaline pH was characterized by upregulation of nhaA and nhaR, which are predicted to encode an Na+/H+ antiporter and transcriptional activator, respectively, as well as sulfate transport and sulfur metabolism genes. Collectively, these results suggest that S. oneidensis modulates multiple transporters, cell envelope components, and pathways of amino acid consumption and central intermediary metabolism as part of its transcriptome response to changing external pH conditions.
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PMID:Transcriptome profiling of Shewanella oneidensis gene expression following exposure to acidic and alkaline pH. 1645 48

Hybrid cluster proteins (HCP) contain two types of Fe/S clusters, namely a [4Fe-4S](2+/1+) or [2Fe-2S](2+/1+) cluster and a novel type of hybrid cluster, [4Fe-2S-2O], in the as-isolated state. Although first isolated from anaerobic sulfate-reducing bacteria, the analysis of the genomic sequences reveals that genes encoding putative hybrid cluster proteins are present in a wide range of organisms, aerobic, anaerobic, or facultative, from the Bacteria, Archaea, and Eukarya domains. Despite a detailed spectroscopic and structural characterization, the precise physiological function of these proteins remained unknown. The present work shows that the transcription of the Escherichia coli hcp gene is induced by hydrogen peroxide, and this induction is regulated by the redox-sensitive transcriptional activator, OxyR. The E. coli hcp mutant strain exhibits higher sensitivity to hydrogen peroxide, a behavior that reverts to the wild type phenotype once a plasmid carrying the hcp gene is reintroduced. Furthermore, the purified HCPs from E. coli and Desulfovibrio desulfuricans ATCC 27774 show an alternative enzymatic activity, which under physiological conditions exhibited K(m) values for hydrogen peroxide (approximately 0.3 mM) within the range of other peroxidases. Altogether, the results reveal that HCP is involved in oxidative stress protection.
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PMID:The role of the hybrid cluster protein in oxidative stress defense. 1692 82

Rhodobacter capsulatus can efficiently grow with taurine as the sole sulfur source. The products of the tpa-tauR-xsc gene region are essential for this activity. TauR, a MocR-like member of the GntR superfamily of transcriptional regulators, activates tpa transcription, as shown by analysis of wild-type and tauR mutant strains carrying a tpa-lacZ reporter fusion. Activation of the tpa promoter requires taurine but is not inhibited by sulfate, which is the preferred sulfur source. TauR directly binds to the tpa promoter, as demonstrated by DNA mobility shift assays. As expected for a transcriptional activator, the TauR binding site is located upstream of the transcription start site, which has been determined by primer extension. Site-directed promoter mutations reveal that TauR binds to direct repeats, an unusual property that has to date been shown for only one other member of the MocR subfamily, namely, GabR from Bacillus subtilis. In contrast, all other members of the GntR family analyzed so far bind to inverted repeats.
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PMID:The GntR-like regulator TauR activates expression of taurine utilization genes in Rhodobacter capsulatus. 1798 66


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