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Query: UNIPROT:P51532 (transcriptional activator)
 6,546 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Activating transcription factor (ATF) is a mammalian transcriptional activator, which is involved in the expression of many viral E1a-inducible and cellular cAMP-inducible genes. Here we identify from the yeast Saccharomyces cerevisiae a previously uncharacterized protein whose DNA binding specificity is like mammalian ATF. We purify this protein (yATF) and show that it is a 66-kDa polypeptide. Finally, we demonstrate that a mammalian ATF site can function as an upstream activating sequence in S. cerevisiae. Taken together, our results suggest that yATF is a previously uncharacterized S. cerevisiae transcriptional activator.
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PMID:Identification and purification of a Saccharomyces cerevisiae protein with the DNA binding specificity of mammalian activating transcription factor. 264 94

It has been proposed in several eukaryotic systems that the regulation of gene transcription involves phosphorylation of specific transcription factors. We report here that the yeast transcriptional activator ADR1 is phosphorylated in vitro by cyclic AMP-dependent protein kinase and that mutations which enhance the ability of ADR1 to activate ADH2 expression decrease ADR1 phosphorylation. We also show that increased kinase activity in vivo inhibits ADH2 expression in an ADR1 allele-specific manner. Our data suggest that glucose repression of ADH2 is in part mediated through a cAMP-dependent phosphorylation-inactivation of the ADR1 regulatory protein.
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PMID:Cyclic AMP-dependent protein kinase phosphorylates and inactivates the yeast transcriptional activator ADR1. 264 45

The FNR protein of E. coli is a transcriptional activator required for the expression of genes involved in anaerobic respiratory pathways. Site-directed mutagenesis was used to alter three amino acids in the recognition helix of the putative DNA-binding domain of FNR, with the aim of changing its specificity to that of the cyclic AMP receptor protein (CRP). In the presence of the mutant protein (FNR-215) expression of the lac operon was activated during anaerobiosis and unaffected by glucose. FNR-215 did not have a uniform effect on the expression of other cAMP-CRP-dependent genes, but the results demonstrate the fundamental similarity between FNR- and CRP-mediated transcriptional activation.
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PMID:Activation of the lac operon of Escherichia coli by a mutant FNR protein. 283 28

Expression of the Escherichia coli maltose regulon is controlled by MalT, a transcriptional activator (Mr = 102,288) encoded by the malT gene. Activation of transcription depends on the presence of the inducer, maltotriose. Using an in vitro transcription/translation assay to monitor the protein, we have purified MalT in native form from MalT-overproducing bacteria. The purified protein is able to promote transcription from different MalT-controlled promoters in well-defined in vitro systems. Maltotriose and the MalT protein suffice to stimulate initiation of transcription at malPp by the E. coli RNA polymerase holoenzyme. In contrast, both MalT protein and cAMP receptor protein are required with their respective effectors, maltotriose and cyclic AMP, for activation of malEp. These data are in agreement with in vivo observations. In addition, we present evidence that MalT is an ATP-binding protein, a result suggesting that ATP may play a role in transcription initiation.
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PMID:Purification and properties of the MalT protein, the transcription activator of the Escherichia coli maltose regulon. 330 11

LuxR, the Vibrio fischeri luminescence gene (lux) activator, is the best-studied member of a family of bacterial transcription factors required for cell density-dependent expression of specific genes involved in associations with eukaryotic hosts. Neither LuxR nor any other LuxR homolog has been shown to bind DNA directly. We have purified the LuxR C-terminal transcriptional activator domain from extracts of recombinant Escherichia coli in which this polypeptide was expressed. The purified polypeptide by itself binds to lux regulatory DNA upstream of the lux box, a 20-bp palindrome that is required for LuxR activity in vivo, but it does not bind to the lux box. However, the LuxR C-terminal domain together with RNA polymerase protects a region including the lux box and the lux operon promoter from DNase I cleavage. There is very little protection of the lux operon promoter region from DNase I digestion in the presence of RNA polymerase alone. Apparently, there is a synergistic binding of the LuxR C-terminal domain and RNA polymerase to the promoter region. The upstream binding region for the purified polypeptide encompasses a binding site for cAMP receptor protein (CRP). Under some conditions, CRP binding can block the binding of the LuxR C-terminal domain to the upstream binding region, and it can also block the synergistic binding of the LuxR C-terminal domain and RNA polymerase to the lux box and luminescence gene promoter region. This description of DNA binding by the LuxR C-terminal domain should lead to an understanding of the molecular interactions of the LuxR family of transcriptional activators with regulatory DNA.
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PMID:Synergistic binding of the Vibrio fischeri LuxR transcriptional activator domain and RNA polymerase to the lux promoter region. 780 88

Overexpression of the YAP1 transcriptional activator renders yeast cells resistant to multiple metabolic inhibitors. In an effort to identify other gene products required for this phenotype we have isolated genomic mutations which neutralize this effect. One such mutation was further characterized and the affected gene was shown to be identical to TPS2 which encodes trehalose phosphate phosphatase, an enzyme catalysing the second step in trehalose biosynthesis. We have analysed the transcriptional regulation of the TPS2 gene and have shown that its transcription is induced by a variety of stressful conditions caused by metabolic inhibitors, osmotic shock and heat shock. This transcriptional activation is mediated by multiple stress promoter elements (C4T) and requires the function of Yap1p as well as reduced activity of the cAMP-regulated protein kinase. Using an appropriate reporter gene we have shown that Yap1p is generally required for transcriptional regulation through the C4T stress element. These results show that the YAP1 protein has a pivotal role in the metabolic stress response and the acquisition of stress tolerance.
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PMID:Yap1p, a yeast transcriptional activator that mediates multidrug resistance, regulates the metabolic stress response. 807 99

During Dictyostelium development, the cAMP-regulated induction of cell-type-specific late genes marks a developmental switch from the initial formation of the multicellular organism to the differentiation of the various cell types that mediate morphogenesis and eventually give rise to the mature fruting body. The G-box binding factor (GBF) is a developmentally regulated Dictyostelium transcription factor whose affinity for a DNA sequence correlates with the ability of that sequence to confer inducibility to late gene promoters in response to high, continuous levels of extracellular cAMP. We report the purification of GBF and cloning of the gene that encodes it, as confirmed by in vitro production of GBF activity. The predicted protein is highly basic and contains two putative zinc fingers. Disruption of the GBF gene by homologous recombination results in the loss of all GBF DNA-binding activity, developmental arrest at the loose aggregate stage, and the loss of late gene induction during development or in response to extracellular cAMP. Constitutive expression of GBF complements the null phenotype and allows for the rapid activation of a class of late genes in response to cAMP. Our results indicate that GBF acts as an extracellular cAMP-responsive transcriptional activator regulating late gene expression and is an essential component of a developmental switch between aggregation and cellular morphogenesis.
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PMID:Cloning and characterization of the G-box binding factor, an essential component of the developmental switch between early and late development in Dictyostelium. 812 61

The core promoter of the human DNA beta-polymerase (beta-pol) gene is regulated by proteins binding at 3 GC boxes and the single activating transcription factor/cAMP response element (ATF/CRE) centered at -45; the central 8 residues of this ATF/CRE match the ATF/CRE consensus sequence, TGACGTCA. Previously, we purified a beta-pol promoter ATF/CRE-binding protein (named palindrome-binding protein or PBP) from bovine testes and found that this protein is a beta-pol promoter transcriptional activator in vitro using a HeLa nuclear extract transcription system (Widen, S. G., and Wilson, S. H. (1991) Biochemistry 30, 6296-6305). In this study, we determined the mechanism of in vitro transcriptional activation by this purified PBP. We used a PBP-depleted HeLa nuclear extract transcription system with an artificial promoter containing a solitary activator element corresponding to the entire 22-nucleotide beta-pol promoter ATF/CRE-binding site. Kinetic analyses of the 180-nucleotide run-off product formation indicated that stimulation of transcriptional activity by PBP was due entirely to an increase in the rate constant for promoter clearance. Thus, under our conditions, the purified PBP had no effect on the rate of closed preinitiation complex formation or for the closed complex to open complex transition. Instead, the rate of productive initiation leading to the 180-nucleotide transcript was stimulated by PBP. We found that the rate of closed preinitiation complex formation was not in rapid equilibrium with promoter and RNA polymerase II, in contrast to the model with prokaryotic RNA polymerase transcription. The results also indicated that PBP binding to the ATF/CRE is required for the stimulation of promoter clearance. These studies define the kinetic mechanism of a purified ATF/CRE-binding protein in stimulation of the in vitro transcription of a designed mammalian promoter.
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PMID:RNA polymerase II transcription. Rate of promoter clearance is enhanced by a purified activating transcription factor/cAMP response element-binding protein. 817 88

Nuclear levels of c-Jun, JunB, c-Fos, and LRF-1 (liver regeneration factor) are high for a large fraction of the G1 phase in regenerating liver and mitogen-stimulated hepatic cells. Previously, JunB was regarded as a less potent transcriptional activator than c-Jun that could also function as a repressor. However, we found that, like c-Jun, JunB alone or LRF-1/JunB strongly transactivates a cAMP-responsive promoter. Unlike c-Jun, JunB represses several AP-1 or activator of transcription factor site-containing promoters, and this inhibition is greatly enhanced in the presence of LRF-1. Here, we identify separate regions of JunB required for trans-activation and repression of these promoters. Deletion analysis shows that the region involved in trans-activation function is highly conserved among all Jun family members and corresponds to activator domain (A1) of c-Jun. In contrast, repression is maximal in the presence of both the DNA-binding domain and a region proximal to the basic region that is highly divergent among Jun proteins. Functional distinctions between Jun proteins during induction of the growth response and tumorigenesis may be accounted for by promoter-specific activation and repression mediated by regional differences in Jun family proteins.
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PMID:Promoter-specific trans-activation and inhibition mediated by JunB. 833 92

The human T-cell leukemia virus type I (HTLV-I)-encoded transcriptional activator protein Tax is strongly implicated in HTLV-I pathogenesis. Tax regulates HTLV-I gene expression through three 21-base pair (bp) repeat enhancer elements located in the transcriptional control region of the virus. Tax does not bind these elements directly, but mediates transactivation through the cellular transcription factors that recognize a cAMP response element (CRE)-like sequence centered within each of the 21-bp repeats. In this report, we identify activating transcription factor-2 (ATF-2) and CRE-binding protein (CREB) as the principal T-cell proteins that bind the three 21-bp repeats in vitro. Purified Tax protein augments the level of RNA synthesis induced by ATF-2 and CREB in a cell-free transcription assay, providing evidence that Tax cooperates with these cellular proteins to activate HTLV-I transcription. Furthermore, Tax dramatically increases the binding of both the T-cell-derived and recombinant forms of ATF-2 and CREB to each of the 21-bp repeats. The target sequences for this enhancement reside within the DNA binding/dimerization domains of these proteins. These data suggest that Tax transactivates HTLV-I gene expression by increasing the number of bound ATF-2 and CREB molecules at the viral promoter.
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PMID:Transactivation by the human T-cell leukemia virus Tax protein is mediated through enhanced binding of activating transcription factor-2 (ATF-2) ATF-2 response and cAMP element-binding protein (CREB). 840 59


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