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 yeast transcriptional activator GAL4 binds specific sites on DNA to activate transcription of adjacent genes. The distinct activating regions of GAL4 are rich in acidic residues and it has been suggested that these regions interact with another protein component of the transcriptional machinery (such as the TATA-binding protein or RNA polymerase II) while the DNA-binding region serves to position the activating region near the gene. Here we show that various GAL4 derivatives, when expressed at high levels in yeast, inhibit transcription of certain genes lacking GAL4 binding sites, that more efficient activators inhibit more strongly and that inhibition does not depend on the DNA-binding domain. We suggest that this inhibition, which we call squelching, reflects titration of a transcription factor by the activating region of GAL4.
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PMID:Negative effect of the transcriptional activator GAL4. 341 49

The bacteriophage lambda transcriptional activator protein, cII, coordinately regulates transcription from two phage promoters that control lysogenic development. We demonstrate that cII is a DNA binding protein that selectively interacts with a repeat sequence in the -35 region of the promoter. Furthermore, cII is shown to bind mainly one face of the DNA helix and to make its contacts primarily in the major groove of the DNA. RNA polymerase sees this same region from the opposite side and sandwiches the DNA helix between itself and cII.
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PMID:Bacteriophage lambda protein cII binds promoters on the opposite face of the DNA helix from RNA polymerase. 622 25

Fli-1, an ets related gene, was found to be rearranged in 75% of erythroleukemias induced by Friend murine leukemia virus. We have shown previously that the Fli-1 gene codes for a sequence specific transcriptional activator which contains two autonomous transcriptional activation domains, one at the amino terminal region and the other at the carboxy terminal region. Recently human Fli-1 gene was shown to be involved in Ewing's sarcoma and related subtypes of primitive neuroectodermal tumors which share t(11;22) (q24;q12) chromosome translocation. In these tumors the carboxyl terminal region of Fli-1 was found to be fused with the amino terminal region of a putative RNA binding protein, EWS. Because part of the amino terminal transcriptional activation domain of Fli-1 was replaced with the amino terminal domain of the EWS (NTD-EWS) which shares homology with RNA polymerase II, it was speculated that NTD-EWS may interfere with RNA pol II function. Alternatively, NTD-EWS could also contribute to the transcriptional activation function of EWS/Fli-1 chimeric protein by providing either a modulatory/regulatory domain or a novel transcriptional activation domain. Here we show that EWS/Fli-1 chimeric protein functions as a transcriptional activator. Deletion analysis reveals that the EWS domain functions as a modulatory/regulatory domain for the transcriptional activation properties of the carboxy terminal transcriptional activation domain of EWS/Fli-1. We therefore propose that replacement of the amino terminal transcriptional activation domain of the Fli-1 protein with the regulatory domain of NTD-EWS results in the activation of the carboxy terminal transcriptional activation domain of Fli-1 which may be the molecular mechanism involved in these human tumors.
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PMID:EWS/Fli-1 chimeric protein is a transcriptional activator. 750 13

Overproduction of the alpha subunit of RNA polymerase in Escherichia coli resulted in inhibition of transcription of two osmoregulated porin genes, ompF and ompC, but not of constitutively expressed housekeeping genes. Overproduction of the sigma subunit did not have any inhibitory effects. The specific inhibitory effect of the alpha subunit was also found to depend upon the OmpR protein, the transcriptional activator for ompF and ompC. These results are in general agreement with other biochemical and genetic evidence suggesting that the alpha subunit is the subunit of RNA polymerase that directly interacts with certain transcriptional activators to initiate transcription.
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PMID:The alpha subunit of RNA polymerase specifically inhibits expression of the porin genes ompF and ompC in vivo and in vitro in Escherichia coli. 751 Feb 55

In order to examine whether splicing can occur cotranscriptionally in mammalian nuclei, we mapped exon-intron boundaries on nascent RNA chains transcribed by RNA polymerase II. A procedure that allows fractionation of nuclei into a chromatin pellet containing DNA, histones, and ternary transcription complexes and a supernatant containing the bulk of the nonhistone proteins and RNAs that are released from their DNA templates was developed. The transcripts of the genes encoding DBP, a transcriptional activator protein, and HMG coenzyme A reductase recovered from the chromatin pellet and the supernatant were analyzed by S1 nuclease mapping. The large majority of the RNA molecules from the pellet appeared to be nascent transcripts, since, in contrast to the transcripts present in the supernatant, they were not cleaved at the polyadenylation site but rather contained heterogeneous 3' termini encompassing this site. Splicing intermediates could be detected among nascent and released transcripts, suggesting that splicing occurs both cotranscriptionally and posttranscriptionally. Our results also indicate that polyadenylation is not required for the splicing of the last DBP intron. In addition to allowing detailed structural analysis of nascent RNA chains, the physical isolation of nascent transcripts also yields reliable measurements of relative transcription rates.
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PMID:Physical isolation of nascent RNA chains transcribed by RNA polymerase II: evidence for cotranscriptional splicing. 752 61

The protein kinase MO15/CDK7 has recently been shown to be associated with the general transcription factor TFIIH and to be capable of phosphorylating the RNA polymerase II carboxy-terminal domain. Here, we show that a monoclonal MO15/CDK7 antibody coimmunoprecipitates, from a rat liver nuclear extract, all components of the RNA polymerase II transcription apparatus required for initiation at the albumin and adenovirus major late promoters. The immunoprecipitate includes RNA polymerase II, TFIID, TFIIB, TFIIH, TFIIF, and TFIIE, but is devoid of transcriptional activator proteins, such as HNF1, HNF4, and C/EBP alpha. The finding of an autonomously initiating RNA polymerase II holoenzyme in mammalian cells suggests conceptual similarities between transcription initiation in prokaryotes and eukaryotes.
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PMID:A mammalian RNA polymerase II holoenzyme containing all components required for promoter-specific transcription initiation. 755 66

Transcription of the nitrogen-regulated nac promoter of Klebsiella aerogenes requires sigma54 RNA polymerase, is activated by the phosphorylated form of the transcription factor nitrogen regulator I (NRI) (NtrC), and is repressed by the product of the nac gene, Nac. Nac protects a large portion of the nac control region, extending from positions -130 to -70, from digestion by DNase I. This site(s) lies immediately upstream from the site at which sigma 54 RNA polymerase binds, is downstream of a high-affinity binding site for the transcriptional activator NRI approximately P, and partially overlaps a low-affinity NRI approximately P-binding site. Binding of Nac to the DNA resulted in bending of the DNA but did not interfere with the binding of sigma 54 RNA polymerase to the promoter or with the binding of NRI approximately P to either the high-affinity site or low-affinity site. Furthermore, transcription assays with various wild-type and mutant templates suggested that Nac did not exclude NRI approximately P from either the low- or high-affinity sites, nor did Nac interfere with the ability of the polymerase to form the open complex when the binding sites for NRI approximately P were moved to different locations upstream from the promoter. Rather, Nac seemed to repress by an antiactivation mechanism in which the interaction of the NRI approximately P, bound at its normal sites, with sigma 54 RNA polymerase, bound to the promoter, was prevented.
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PMID:Repression of the Klebsiella aerogenes nac promoter. 755 39

Recent work has established that the Escherichia coli RNA polymerase alpha subunit consists of an amino-terminal domain containing determinants for interaction with the remainder of RNA polymerase, a carboxy-terminal domain containing determinants for interaction with DNA and interaction with transcriptional activator proteins, and a 13-36 amino acid unstructured and/or flexible linker. These findings suggest a simple, integrated model for the mechanism of involvement of alpha in promoter recognition and transcriptional activation.
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PMID:The Escherichia coli RNA polymerase alpha subunit: structure and function. 761 89

Infection of cells with herpes simplex virus type 1 (HSV-1) results in a rapid alteration of phosphorylation on the large subunit of cellular RNA polymerase II (RNAP II), most likely on its C-terminal domain (S. A. Rice, M. C. Long, V. Lam, C. A. Spencer, J. Virol. 68:988-1001, 1994). This phosphorylation modification generates a novel form of the large subunit which we have designed IIi. In this study, we examine roles that HSV-1 gene products play in this process. An HSV-1 mutant defective in the immediate-early transcriptional activator protein ICP4 is able to efficiently induce IIi. Viruses having mutations in the genes for the ICP0, ICP6, or ICP27 proteins are also competent for IIi formation. In contrast, 22/n199, an HSV-1 mutant which contains a nonsense mutation in the gene encoding the immediate-early protein ICP22, is significantly deficient in IIi induction. This effect is seen in Vero cells, where 22/n199 grows relatively efficiently, and in human embryonic lung (HEL) cells, where 22/n199 growth in more restricted. RNAP II is recruited into viral replication compartments in 22/n199-infected cells, indicating that altered phosphorylation of RNAP II is not a prerequisite for nuclear relocalization of RNAP II. In addition, we show by nuclear run-on transcription analysis that viral gene transcription is deficient in HEL cells infected with 22/n199. Viral late gene transcription does not occur efficiently, and antisense transcription throughout the genome is diminished compared with that of the wild-type HSV-1 infection. These transcriptional effects cannot be explained by differences in viral DNA replication, since 22/n199 replicates its DNA efficiently in HEL cells. Our results demonstrated that ICP22 is necessary for virus-induced aberrant phosphorylation of RNAP II and for normal patterns of viral gene transcription in certain cell lines.
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PMID:Herpes simplex virus immediate-early protein ICP22 is required for viral modification of host RNA polymerase II and establishment of the normal viral transcription program. 763

The PhoB protein, the transcriptional activator for the genes belonging to the phosphate regulon in Escherichia coli, was autophosphorylated in the presence of acetyl phosphate (acP) in vitro. The properties of phospho-PhoB, such as stability upon acid or alkali treatment and activating pstS transcription by RNA polymerase holoenzyme, were the same as those of phospho-PhoB produced from phospho-PhoR or phospho-PhoM. These results indicate that PhoB is an enzyme that catalyzes its own phosphorylation using acP, a low-molecular-weight metabolic intermediate.
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PMID:Autophosphorylation and activation of transcriptional activator PhoB of Escherichia coli by acetyl phosphate in vitro. 764 40


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