Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:2.7.7.6 (RNA polymerase)
34,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The purified TyrR protein and phenylalanine were sufficient to activate in vitro transcription from the tyrP promoter by wild-type RNA polymerase. Such TyrR-mediated activation did not occur when the mutant alpha 235 RNA polymerase was used, indicating that TyrR is a class I transcription activator.
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PMID:The TyrR protein of Escherichia coli is a class I transcription activator. 779 38

In Bordetella pertussis, expression of virulence factors is controlled by the Bvg proteins, which comprise a sensor-regulator two-component signal transduction system. Previously, we described a mutant strain of B. pertussis that had reduced transcription of pertussis toxin and adenylate cyclase toxin genes, while other virulence factors were relatively unaffected. We obtained a B. pertussis clone that repaired the defect in both this strain and an independent mutant strain with a similar phenotype when introduced onto the chromosome by allelic exchange. Further analysis revealed that the mutations were just upstream of the translational start site of the rpoA gene encoding the alpha subunit of RNA polymerase. We confirmed that these mutations were responsible for the mutant phenotype by site-directed mutagenesis. Our hypothesis that these mutations cause an overexpression of rpoA was confirmed by Western immunoblotting and translational fusion analysis. Corroboration of this effect was obtained by overexpressing rpoA on a plasmid in wild-type B. pertussis, which caused the same phenotype as the mutants showed. Conclusions in regard to the identity of the transcription activator of the toxin genes are discussed.
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PMID:Effect of mutations causing overexpression of RNA polymerase alpha subunit on regulation of virulence factors in Bordetella pertussis. 796 98

DNAase I footprinting has been used to study open complexes between Escherichia coli RNA polymerase and the galactose operon P1 promoter, both in the absence and the presence of CRP (the cyclic AMP receptor protein, a transcription activator). From the effects of deletion of the C-terminal part of the RNA polymerase alpha subunit, we deduce that alpha binds at the upstream end of both the binary RNA polymerase-galP1 and ternary RNA polymerase-CRP-galP1 complexes. Disruption of the alpha-upstream contact suppresses open complex formation at galP1 at lower temperatures. In ternary RNA polymerase-CRP-galP1 complexes, alpha appears to make direct contact with Activating Region 1 in CRP. DNAase I footprinting has been used to detect and quantify interactions between purified alpha and CRP bound at galP1.
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PMID:Interactions between the cyclic AMP receptor protein and the alpha subunit of RNA polymerase at the Escherichia coli galactose operon P1 promoter. 797 Dec 67

The mammalian transcription activator protein UBF contains five tandemly repeated HMG homology domains which are required for DNA binding. We have used highly purified RNA polymerase I (Pol I) and upstream binding factor (UBF) and investigated whether these two proteins interact in solution. We show by a variety of different experimental approaches, such as immunoprecipitation, glycerol gradient sedimentation, affinity chromatography and protein blotting, that UBF physically associates with Pol I. Mutational analysis reveals that the HMG boxes play an important role in this specific interaction. UBF binds to mouse and yeast Pol I, demonstrating that the interaction of UBF with Pol I has been conserved during evolution. Interestingly, in both species one Pol I-specific subunit (34.5 kDa in yeast and 62 kDa in mouse) was recognized by UBF. No specific interaction was observed with Pol II. Unexpectedly, UBF was found to associate also with a unique subunit of yeast Pol III. This apparent specific interaction of UBF with the two classes of RNA polymerases may reflect functionally important interactions of HMG box-containing transcription factors with the transcriptional apparatus.
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PMID:The HMG box-containing nucleolar transcription factor UBF interacts with a specific subunit of RNA polymerase I. 830 61

Protein-protein interactions between transcription activator proteins and RNA polymerase or basal transcription factors have been suggested to be important for transcription activation. Interactions between catabolite gene activator protein (CAP) and RNA polymerase have been proposed based on face-of-helix-dependent transcription activation by CAP and based on face-of-helix-dependent cooperative binding of CAP and RNA polymerase to promoter DNA. Mutants of CAP specifically defective in transcription activation have been isolated (mutants defective in transcription activation, but not defective in DNA binding and DNA bending). All such mutants contain amino-acid substitutions within a surface loop consisting of amino acids 152 to 166 of CAP. Here we use the thermodynamically rigorous technique of fluorescence polarization to show that CAP interacts with RNA polymerase in solution in the absence of promoter DNA (KD,app = 2.8 x 10(-7) M), whereas [Ala158]CAP, a mutant of CAP specifically defective in transcription activation, does not.
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PMID:CAP interacts with RNA polymerase in solution in the absence of promoter DNA. 839 48

The Saccharomyces cerevisiae SPT2 gene was identified by genetic screens for mutations which are suppressors of Ty and delta insertional mutations at the HIS4 locus. The ability of spt2 mutations to suppress the transcriptional interference caused by the delta promoter insertion his-4-912 delta correlates with an increase in wild-type HIS4 mRNA levels. The SPT2 gene is identical to SIN1, which codes for a factor genetically defined as a negative regulator of HO transcription. Mutations in SPT2/SIN1 suppress the effects of trans-acting mutations in SWI genes and of partial deletions in the C-terminal domain of the largest subunit of RNA polymerase II. Nuclear localization and protein sequence similarities suggested that the SPT2/SIN1 protein may be related to the nonhistone chromosomal protein HMG1. To assess the significance of this structural similarity and identify domains of SPT2 functionally important in the regulation of his4-912 delta, we have studied recessive and dominant spt2 mutations created by in vitro mutagenesis. We show here that several alleles carrying C-terminal deletions as well as point mutations in the C-terminal domain of the SPT2 protein exhibit a dominant suppressor phenotype. C-terminal basic residues necessary for wild-type SPT2 protein function which are absent from HMG1 have been identified. The competence of these mutant SPT2 proteins to interfere with the maintenance of the His- (Spt+) phenotype of a his4-912 delta SPT2+ strain is lost by deletion of internal HMG1-like sequences and is sensitive to the wild-type SPT2+ gene dosage. Using cross-reacting antipeptide polyclonal antibodies, we demonstrate that the intracellular level of the wild-type SPT2 protein is not affected in presence of dominant mutations and furthermore that the reversion of the dominance by internal deletion of HMG1-like sequences is not mediated by altered production or stability of the mutant polypeptides. Our results suggest that the products of dominant alleles directly compete with the wild-type protein. On the basis of primary sequence similarities, we propose that an HMG-box-like motif is required for SPT2 function in vivo and that this motif also is necessary for the dominant suppressor phenotype exhibited by some mutant SPT2 alleles.
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PMID:Mutational and functional analysis of dominant SPT2 (SIN1) suppressor alleles in Saccharomyces cerevisiae. 839 4

A system that detects the formation of complexes between different proteins by linking them to separate domains of the GAL4 transcription activator protein has been used to study protein-protein interactions between four essential and unique subunits of yeast RNA polymerase III (C82, C53, C34 and C31), the 70-kDa component of the initiation transcription factor IIIB (TFIIIB70) and the TATA-binding protein. We found that C82, C34, and C31 are able to combine with each other in vivo and that C34 interacts with TFIIIB70. These results suggest that C34 and TFIIIB70 are specificity determinants of the RNA polymerase III-TFIIIB interaction.
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PMID:Interaction between a complex of RNA polymerase III subunits and the 70-kDa component of transcription factor IIIB. 840 94

Regulation of glutamine-synthetase (GS) activity in enteric bacteria involves a complex cascade of events. In response to nitrogen limitation, a transferase catalyses the uridylylation of the PII protein, which in turn stimulates deadenylylation of GS. Deadenylylated GS is the more active form of the enzyme. Here we characterize in detail the genes from Escherichia coli encoding uridylyl-transferase (glnD), the PII protein (glnB), and adenylyl-transferase (glnE). glnD is transcribed from its own promoter, glnE is contranscribed with another gene, orfXE, whereas glnB is partly contranscribed with a gene encoding a homologue of the transcription activator NtrC. All three gln regulatory genes were constitutively expressed at a low level, i.e. their expression was independent of the nitrogen status and the RNA polymerase sigma factor sigma 54. We conclude that the functioning of the GS adenylylation cascade is regulated by modulation of the activities of uridylyl-transferase and adenylyl-transferase, rather than by changes in the expression of their genes.
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PMID:The genes of the glutamine synthetase adenylylation cascade are not regulated by nitrogen in Escherichia coli. 841 94

The RNA polymerase II holoenzyme contains RNA polymerase II, a subset of general transcription factors and SRB regulatory proteins. We report here that SWI and SNF gene products, previously identified as global gene regulators whose functions include remodeling chromatin, are also integral components of the yeast RNA polymerase II holoenzyme. The SWI/SNF proteins are components of the SRB complex, also known as the mediator, which is tightly associated with the RNA polymerase II C-terminal repeat domain. The SWI/SNF components provide the holoenzyme with the capacity to disrupt nucleosomal DNA and thus facilitate stable binding of various components of the transcription initiation complex at promoters.
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PMID:RNA polymerase II holoenzyme contains SWI/SNF regulators involved in chromatin remodeling. 856 69

The SWI1/ADR6, SWI2/SNF2, SWI3, SNF5, and SNF6 gene products are all required for proper transcriptional control of many genes in the yeast Saccharomyces cerevisiae. Genetic studies indicated that these gene products might form a multiprotein SWI/SNF complex important for chromatin transitions preceding transcription from RNA polymerase II promoters. Biochemical studies identified a SWI/SNF complex containing these and at least six additional polypeptides. Here we show that the 29-kDa component of the SWI/SNF complex is identical to TFG3/TAF30/ANC1. Thus, a component of the SWI/SNF complex is also a member of the TFIIF and TFIID transcription complexes. TFG3 interacted with the SNF5 component of the SWI/SNF complex in protein interaction blots. TFG3 is significantly similar to ENL and AF-9, two proteins implicated in human acute leukemia. These results suggest that ENL and AF-9 proteins interact with the SNF5 component of the human SWI/SNF complex and raise the possibility that the SWI/SNF complex is involved in acute leukemia.
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PMID:TFG/TAF30/ANC1, a component of the yeast SWI/SNF complex that is similar to the leukemogenic proteins ENL and AF-9. 866 46


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