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)

Tax1 of human T-cell leukemia virus type 1 (HTLV-1) activates viral transcription dependent upon three 21-bp enhancer elements in the long terminal repeat. Difficulties in detecting any association of Tax1 with the viral enhancer have hampered elucidation of the molecular mechanisms of Tax1-mediated transcriptional activation. By constructing a fusion protein with the heterologous DNA-binding domain of yeast GAL4, Tax1 was shown to be a potent transcriptional activator dependent on the presence of GAL4-binding sites. Deletions of the Tax1 portion of the fusion protein revealed that almost the entire region of Tax1 (amino acids 2-337) is required for activation, and the activity correlated well with that of the viral enhancer. The GAL/Tax1 mutant lacking 41 residues of the C-terminus of Tax1, GAL/Tax1(2-312), was inactive for the viral enhancer, but activity was recovered by adding the heterologous activation domain of herpes simplex virus VP16. These results indicate that Tax1 has two distinct but overlapping functional domains for transcriptional activation and for enhancer specificity. Thus, Tax1 is thought to be a transcription factor acting in the enhancer complex rather than as a catalytic or allosteric modifier of pre-existing cellular transcription factors.
Oncogene 1991 Dec
PMID:HTLV-1 Tax has distinct but overlapping domains for transcriptional activation and for enhancer specificity. 176 79

The significance of intracellular iron levels of Escherichia coli on the expression of the fumarate reductase operon (frd), which is regulated by the transcriptional activator FNR, was studied in vivo. The iron contents of aerobically and anaerobically grown E. coli were determined and related to the expression of frd and of genes (fiu, fepA, fhuF) which are regulated by the iron uptake regulatory protein Fur. The iron contents varied from 1.6 to 6.9 mumol Fe/g protein with no significant difference in aerobic and anaerobic bacteria. Expression of frd was not related to the different iron levels, but to oxygen supply. Only severe iron limitation in iron-depleted medium, which caused lower iron contents (0.8 to 1.6 mumol/g), reduced the expression of frd under anaerobic conditions. On the other hand, expression of fiu, fepA and fhuF clearly responded to iron supply and cellular content, but only slightly to changed O2 supply. Generally, expression of frd responded only to much stricter iron limitation, than expression of Fur regulated genes. It is concluded that the functional state of FNR during aerobic/anaerobic switch is not regulated by iron content and reversible binding of Fe2+ under physiological conditions. Therefore FNR does not communicate with the iron pool regulating the Fur protein.
FEMS Microbiol Lett 1991 Dec 01
PMID:Iron content and FNR-dependent gene regulation in Escherichia coli. 180 64

The cpeBA operon of the Group III chromatically adapting cyanobacterium Pseudanabaena species PCC 7409 was cloned, sequenced and characterized. The cpeBA genes are transcribed in green-light-grown cells as an abundant 1400-nucleotide mRNA which initiates 69 nucleotides upstream from the cpeB translation start. Extensive sequence identity, extending 70 nucleotides 5' to the transcription start, occurs among cpeBA promoters of Group II and III chromatic adapters. Cell extracts of green-light-grown Calothrix species PCC 7601 contain an activity which specifically binds a restriction fragment containing the Pseudanabanea species PCC 7409 cpeBA promoter. Green-light-dependent cpeBA transcription in Group II and III chromatically adapting cyanobacteria is suggested to be similarly controlled by a transcriptional activator.
Mol Microbiol 1991 Dec
PMID:Molecular cloning and transcriptional analysis of the cpeBA operon of the cyanobacterium Pseudanabaena species PCC7409. 180 46

We have cloned the negative regulatory gene (DAL80) of the allantoin catabolic pathway, characterized its structure, and determined the physiological conditions that control DAL80 expression and its influence on the expression of nitrogen catabolic genes. Disruption of the DAL80 gene demonstrated that it regulates multiple nitrogen catabolic pathways. Inducer-independent expression was observed for the allantoin pathway genes DAL7 and DUR1,2, as well as the UGA1 gene required for gamma-aminobutyrate catabolism in the disruption mutant. DAL80 transcription was itself highly sensitive to nitrogen catabolite repression (NCR), and its promoter contained 12 sequences homologous to the NCR-sensitive UASNTR. The deduced DAL80 protein structure contains zinc finger and coiled-coil motifs. The DAL80 zinc finger motif possessed high homology to the transcriptional activator proteins required for expression of NCR-sensitive genes in fungi and the yeast GLN3 gene product required for functioning of the NCR-sensitive DAL UASNTR. It was also homologous to the three GATAA-binding proteins reported to be transcriptional activators in avian and mammalian tissues. The latter correlations raise the possibility that both positive and negative regulators of allantoin pathway transcription may bind to similar sequences.
Mol Cell Biol 1991 Dec
PMID:Expression of the DAL80 gene, whose product is homologous to the GATA factors and is a negative regulator of multiple nitrogen catabolic genes in Saccharomyces cerevisiae, is sensitive to nitrogen catabolite repression. 156 60

Transcription initiation from a eukaryotic polymerase II promoter requires a functional interaction of regulatory transcriptional activators with at least one of the basal transcription factors binding in the vicinity of the TATA box. To characterize this type of interaction in vivo, we have inserted the bacterial Tet repressor-operator complex in nine different positions between an enhancer element (as-1) and the TATA box of the cauliflower mosaic virus (CaMV) 35S RNA promoter. A direct contact between the transcriptional activator ASF-1, which binds to as-1, and the transcriptional machinery should be affected by a repressor protein bound between them, as the spacing of only 34 base pairs (bp) between as-1 and the TATA box is too short to allow looping of the DNA around the repressor. In each construct, the distance of 34 bp was kept constant, while the position of the 19-bp tet operator relative to the TATA box differed by 2 bp. Thus, the position of the Tet repressor relative to the plant transcription factors was consecutively changed by 72 degrees, which allowed us to investigate whether repression depended on the stereospecific alignment of the repressor with the transcription factors. Binding of the Tet repressor to the operator blocked transcription only when the operator was inserted less tha 5 bp from the TATA box. In all other promoter derivatives, no inhibitory effect of the repressor was observed, which suggests that ASF-1 does not directly interact with the general transcription machinery.
Proc Natl Acad Sci U S A 1991 Dec 01
PMID:Characterization of the interaction of plant transcription factors using a bacterial repressor protein. 196 11

The hns (27 min) gene encoding the 15.4-kDa nucleoid protein H-NS was shown to belong to the cold shock regulon of Escherichia coli, its expression being enhanced 3- to 4-fold during the growth lag that follows a shift from 37 degrees C to 10 degrees C. A 110-base-pair (bp) DNA fragment containing the promoter of hns fused to a promoterless cat gene (hns-cat fusion) conferred a similar cold shock response to the expression of chloramphenicol acetyltransferase (CAT) activity in vivo and in coupled transcription-translation systems prepared with extracts of cold-shocked cells. Extracts of the same cells produce a specific gel shift of the 110-bp DNA fragment and this fragment, immobilized on a solid support, specifically retains a single 7-kDa protein present only in cold-shocked cells that was found to be identical to F10.6 (CS7.4), the product of cspA. This purified protein, which is homologous to human DNA-binding protein YB-1, recognizes some feature of the 110-bp promoter region of hns and acts as a cold shock transcriptional activator of this gene since it stimulates the expression of CAT activity and of cat transcription in in vitro systems programmed with plasmid DNA carrying the hns-cat fusion.
Proc Natl Acad Sci U S A 1991 Dec 01
PMID:Identification of a cold shock transcriptional enhancer of the Escherichia coli gene encoding nucleoid protein H-NS. 196 61

The v-erbA oncogene is a retrovirus-transduced and altered copy of a cellular gene for a thyroid hormone receptor. In animal cells, the v-erbA protein fails to respond to hormone and acts as a dominant negative allele, inhibiting gene activation normally conferred by the wild-type thyroid hormone receptor. We report here that, unexpectedly, the v-erbA protein acts as a hormone-regulated transcriptional activator in S. cerevisiae. We suggest that the ability of v-erbA protein to function as a transcriptional repressor or an activator is determined by interaction with, or modification by, other cellular factors, and that this phenomenon may be relevant to understanding ligand regulation of the normal thyroid and steroid hormone receptors.
Cell 1990 Dec 21
PMID:The viral erbA oncogene protein, a constitutive repressor in animal cells, is a hormone-regulated activator in yeast. 197 58

A genetic system was developed in Escherichia coli to study leucine zippers with the amino-terminal domain of bacteriophage lambda repressor as a reporter for dimerization. This system was used to analyze the importance of the amino acid side chains at eight positions that form the hydrophobic interface of the leucine zipper dimer from the yeast transcriptional activator, GCN4. When single amino acid substitutions were analyzed, most functional variants contained hydrophobic residues at the dimer interface, while most nonfunctional sequence variants contained strongly polar or helix-breaking residues. In multiple randomization experiments, however, many combinations of hydrophobic residues were found to be nonfunctional, and leucines in the heptad repeat were shown to have a special function in leucine zipper dimerization.
Science 1990 Dec 07
PMID:Sequence requirements for coiled-coils: analysis with lambda repressor-GCN4 leucine zipper fusions. 214 79

IL-1, like other agents that have been shown a capacity to induce protein kinase C, is a potent transcriptional activator of the metalloproteinase, stromelysin, in synovial and other fibroblasts. cAMP has been shown to inhibit stromelysin transcription in fibroblasts of nonsynovial origin, and is regarded as an important second messenger for IL-1. In addition to stimulating metalloproteinase transcription, IL-1 also induces PGE2 production in synoviocytes. We determined that rIL-1 alpha led to the time-dependent accumulation of intracellular cAMP in serum-starved rheumatoid synovial fibroblasts, and that the effect was blocked by indomethacin. The cAMP agonists forskolin, 3-isobutyl-1-methylxanthine, and PGE2 suppressed the IL-1 induction of stromelysin; conversely, indomethacin superinduced IL-1-elicited stromelysin mRNA. These results were recapitulated on the transcriptional level in cells transfected with the rat transin/stromelysin promoter in a reporter (CAT) construct. 2',5'-Dideoxyadenosine, an inhibitor of adenylate cyclase, also augmented the IL-1 induction of stromeylsin mRNA, as did H-8, a specific inhibitor of the cAMP-dependent protein kinase A. Staurosporine and H-7, inhibitors of protein kinase C, blocked the IL-1 induction of stromelysin mRNA. We conclude that IL-1 appears to stimulate at least two transduction pathways in synovial fibroblasts from patients with rheumatoid arthritis, and that these have antagonistic effects on the regulation of stromelysin transcription.
J Immunol 1990 Dec 01
PMID:IL-1 regulation of transin/stromelysin transcription in rheumatoid synovial fibroblasts appears to involve two antagonistic transduction pathways, an inhibitory, prostaglandin-dependent pathway mediated by cAMP, and a stimulatory, protein kinase C-dependent pathway. 217 73

Transcription of the human neurotropic virus promoter, JCVE, and its regulation in glial cells are controlled by the 98 bp tandem repeats positioned between the viral early and late genes. Here, we show that a region, designated domain-D, located upstream from the 98 bp repeats functions as a transcriptional activator and increases JCVE promoter activity. Using the reporter SV40E promoter fused to the bacterial chloramphenicol acetyltransferase (CAT) gene, we demonstrate that domain-D stimulates the basal SV40E promoter activity in glial and to a lesser degree in HeLa cells. Results from gel mobility-shift assays indicate that domain-D interacts with proteins derived from glial and HeLa extracts and results in the formation of specific DNA-protein complexes. Through UV cross-linking assays, we demonstrate that these complexes have similar electrophoretic mobilities which comigrate with the 43-50 Kd proteins derived from glial and HeLa cells. These findings, together with our previous observations, imply that the JCVE control region is composed of multiple common and specific activator domains that may account for the increased expression of the promoter in glial cells. The possible role of the D-binding protein in transcription of the JCVE promoter is discussed.
Nucleic Acids Res 1990 Dec 25
PMID:Regulation of a human neurotropic virus promoter, JCVE: identification of a novel activator domain located upstream from the 98 bp enhancer promoter region. 217 35


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