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

An iron-regulated promoter was cloned on a 2.1 kb Bg/II fragment from Pseudomonas sp. strain M114 and fused to the lacZ reporter gene. Iron-regulated lacZ expression from the resulting construct (pSP1) in strain M114 was mediated via the Fur-like repressor which also regulates siderophore production in this strain. A 390 bp StuI-PstI internal fragment contained the necessary information for iron-regulated promoter expression. This fragment was sequenced and the initiation point for transcription was determined by primer extension analysis. The region directly upstream of the transcription start point contained no significant homology to known promoter consensus sequences. However the -16 to -25 bp region contained homology to four other iron-regulated pseudomonad promoters. Deletion of bases downstream from the transcriptional start did not affect the iron-regulated expression of the promoter. The -37 and -43 bp regions exhibited some homology to the 19 bp Escherichia coli Fur-binding consensus sequence. When expressed in E. coli (via a cloned transacting factor from strain M114) lacZ expression from pSP1 was found to be regulated by iron. A region of greater than 77 bases but less than 131 upstream from the transcriptional start was found to be necessary for promoter activity, further suggesting that a transcriptional activator may be required for expression.
Mol Gen Genet 1991 Aug
PMID:Regulation of iron assimilation: nucleotide sequence analysis of an iron-regulated promoter from a fluorescent pseudomonad. 167 22

The fadR gene of Escherichia coli encodes a protein that acts as a negative regulator (repressor) of the inducible beta-oxidation pathway. We report that the FadR protein also functions as a positive transcriptional activator of the fabA gene, which encodes the enzyme introducing the double bond of the unsaturated fatty acids of E. coli.
J Mol Biol 1991 Dec 20
PMID:Escherichia coli transcription factor that both activates fatty acid synthesis and represses fatty acid degradation. 172 55

The NF-kappa B transcription factor complex is composed of two proteins, designated p50 and p65, both having considerable homology to the product of the rel oncogene. We present evidence that the p65 subunit is a potent transcriptional activator in the apparent absence of the p50 subunit, consistent with in vitro results demonstrating that p65 can interact with DNA on its own. To identify the minimal activation domain, chimeric fusion proteins between the DNA binding domain of the yeast transcriptional activator protein GAL4 and regions of the carboxy terminus of p65 were constructed, and their transcriptional activity was assessed by using a GAL4 upstream activation sequence-driven promoter-chloramphenicol acetyltransferase fusion. This analysis suggests that the boundaries of the activation domain lie between amino acids 415 and 550. Moreover, single amino acid changes within residues 435 to 459 greatly diminished activation. Similar to other activation domains, this region contains a leucine zipper-like motif as well as an overall net negative charge. To identify those residues essential for DNA binding, we made use of a naturally occurring derivative of p65, lacking residues 222 to 231 (hereafter referred to as p65 delta), and produced via an alternative splice site. Gel mobility shift analysis using bacterially expressed p65, p65 delta, and various mutants indicates that residues 222 to 231 are important for binding to kappa B DNA. Coimmunoprecipitation analysis suggests that these residues likely contribute to the multimerization function required for homomeric complex formation or heteromeric complex formation with p50 in that no association of p65 delta with itself or with p50 was evident. However, p65 delta was able to form weak heteromeric complexes with p65 that were greatly reduced in their ability to bind DNA. On the basis of these findings, we suggest that subtle changes within the proposed multimerization domain can elicit different effects with the individual Rel-related proteins and that a potential role of p65 delta may be to negatively regulate NF-kappa B function through formation of nonfunctional heteromeric complexes.
Mol Cell Biol 1992 Feb
PMID:Functional characterization of the NF-kappa B p65 transcriptional activator and an alternatively spliced derivative. 173 26

The full elastolytic phenotype of Pseudomonas aeruginosa requires lasB, the structural gene for elastase, its transcriptional activator lasR, and lasA. The lasB gene was insertionally inactivated with the omega fragment and this mutated gene introduced into the P. aeruginosa chromosome. Replacement of the wild-type gene with the inactivated gene was verified by Southern analysis and confirmed by lack of elastase antigen on Western blots and lack of activity in liquid assays. The mutant did, however, retain elastolytic activity on elastin plates. This residual activity was abolished by inactivation of lasB in PAO-E64, a lasA-deficient mutant, demonstrating that it was due to the lasA gene product. Northern analysis demonstrated that, like lasB, lasA is transcriptionally controlled by the lasR gene product.
Mol Microbiol 1991 Aug
PMID:Pseudomonas aeruginosa LasA: a second elastase under the transcriptional control of lasR. 176 76

The products of a minimum of 15 genes are required for the synthesis of an active formate-hydrogenlyase (FHL) system in Escherichia coli. All are co-ordinately regulated in response to variations in the oxygen and nitrate concentration and the pH of the culture medium. Formate is obligately required for transcriptional activation of these genes. Analysis of the transcription of one of these genes, hycB linked to the lacZ reporter gene, revealed that oxygen and nitrate repression of transcription could be relieved completely, or partially in the case of nitrate, either by the addition of formate to the medium or by increasing the copy number of the gene encoding the transcriptional activator (fhlA) of this regulon. These studies uncovered a further level of regulation in which the transcription of hycB was reduced in cells grown on glucose. This effect was most clearly seen in aerobically grown cells when formate was added externally. Addition of cAMP overcame this glucose repression, which could be shown to be mediated by the cAMP receptor protein. These results would be consistent with the transport of formate being regulated by catabolite repression. Moreover, the repression of transcription through high pH also could be partially overcome by addition of increasing concentrations of formate to the medium, again being consistent with regulation at the level of formate import and export. Taken together, all these observations indicate that it is the intracellular level of formate that determines the transcription of the genes of the formate regulon by FhlA. This represents a novel positive feedback mechanism in which the activator of a regulon induces its own synthesis in response to increases in the concentration of the catabolic substrate, and this in turn is governed by the relative affinities of FhlA and the three formate dehydrogenase isoenzymes for formate.
Mol Microbiol 1991 Nov
PMID:Mechanism of regulation of the formate-hydrogenlyase pathway by oxygen, nitrate, and pH: definition of the formate regulon. 177 67

Crown gall tumorigenesis by Agrobacterium tumefaciens requires the co-ordinate transcriptional induction of a set of pathogenesis genes. At least three classes of environmental stimuli act synergistically to induce these genes: (i) monocyclic aromatic hydrocarbons such as acetosyringone, coniferyl alcohol, and vanillin, (ii) neutral or acidic monosaccharides such as glucose and glucuronic acid, and (iii) acidic pH. Three proteins are required to sense and respond to these stimuli: (i) VirA, a transmembrane sensory protein and histidine protein kinase, (ii) VirG, a transcriptional activator which is phosphorylated by phosphoryl VirA, and (iii) ChvE, a periplasmic sugar-binding protein. VirA and VirG are members of the so-called two-component family of regulatory proteins. This regulatory system continues to offer new discoveries in the areas of signal transduction, host-microbe interactions, and host range.
Mol Microbiol 1991 Oct
PMID:An Agrobacterium two-component regulatory system for the detection of chemicals released from plant wounds. 179 50

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

CPC1 is the transcriptional activator of amino acid biosynthetic genes of Neurospora crassa. CPC1 function in vivo was abolished upon deletion of segments of cpc-1 corresponding to the presumed transcription activation domain, the DNA-binding and dimerization domains, or a 52-residue connector segment of CPC1. A truncated CPC1 polypeptide containing only the carboxy-terminal 57-residue segment of CPC1 was sufficient to form homodimers that bound DNA. However, deletion of the segment of cpc-1 corresponding to the connector segment in the full-length CPC1 polypeptide abolished DNA binding. Removal of a segment of cpc-1 corresponding to the GIn-rich region of CPC1 reduced in vivo function only slightly. The homologous transcription activator of Saccharomyces cerevisiae, GCN4, did not substitute for CPC1 in N. crassa. Chimeric CPC1-GCN4 polypeptides that contained the GCN4 transcriptional activation domain or the domain of GCN4 that corresponds to the essential 52-residue connector segment of CPC1, functioned with reduced efficiency. However, a chimeric polypeptide containing the GCN4 DNA-binding and dimerization domains in place of those of CPC1 functioned essentially as well as wild-type CPC1. The basic and dimerization domains of CPC1 were characterized by introducing deletions or site-directed amino acid replacements. The basic region was required for DNA binding but not for dimerization. CPC1 has a short dimerization domain containing heptad residues Leu-1, Leu-2, Trp-3, and His-4. When Val was substituted for Leu-1 or Leu-2, CPC1 was fully active, but when Val replaced Trp-3, dimerization and DNA binding were prevented. DNA band shift analyses with CPC1 heterodimers demonstrated that CPC1 does not require aligned heptad leucine residues for dimerization. Replacement of two charged residues located between Leu-1 and Leu-2 of CPC1 abolished dimerization and DNA binding.
Mol Cell Biol 1991 Feb
PMID:Characterization of Neurospora CPC1, a bZIP DNA-binding protein that does not require aligned heptad leucines for dimerization. 182 60

We describe here the cloning, characterization and analysis of the regulation of the ARO2 gene of Saccharomyces cerevisiae, the first reported study of a eukaryotic gene encoding chorismate synthase (E.C. 4.6.1.4). The gene contains an ORF of 1128 bp, encoding a protein with a calculated molecular mass of 40.8 kDa. ARO2 is regulated under the 'general control system' for amino acid biosynthesis by the transcriptional activator GCN4 which binds in vitro at three sites within the ARO2 promoter. The ARO2 gene product is highly similar to its Escherichia coli counterpart, with a 47% identity distributed over the entire length of the peptide. We therefore suggest that the S. cerevisiae chorismate synthase, in contrast to the Neurospora crassa enzyme, but like other chorismate synthases, is a monofunctional peptide, solely possessing chorismate synthase activity.
Mol Microbiol 1991 Sep
PMID:Molecular cloning, characterization and analysis of the regulation of the ARO2 gene, encoding chorismate synthase, of Saccharomyces cerevisiae. 183 29

We constructed cell lines containing various enhancer elements cloned upstream from a marker gene. By microinjection of specific antibodies directed against transcriptional activator proteins into these cell lines, we have developed a functional assay for factors which regulate the activity of target promoters. Here we show that microinjection of a highly specific antibody to the cyclic AMP enhancer element-binding (CREB) protein diminishes gene expression in response to cyclic AMP in living fibroblasts.
Mol Cell Biol 1991 Mar
PMID:Induction of a cyclic AMP-responsive gene in living cells requires the nuclear factor CREB. 184 3


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