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 RNA polymerase inhibitor, lomofungin has been used to determine the half life of specific synthetic capacities (invertase and alpha-glucosidase) as well as that for gross protein synthesis. In both cases the studies conclude that cognate messenger RNAs decay with a half life of approximately 20 minutes. This antibiotic has been used to determine the half life of allophanate hydrolase specific synthetic capacity. We find that it decays with a half life of about three minutes; a value that agrees with the decay rates of allophanate hydrolase synthetic capacity following removal of inducer. These observations argue that mRNA may be metabolized by two separate routes in Saccharomyces.
Mol Gen Genet 1975
PMID:Lomofungin inhibition of allophanate hydrolase synthesis in Saccharomyces cerevisiae. 110 15

Hybridization of messenger ribonucleic acid (mRNA) isolated from Escherichia Coli K-12 to deoxyribonucleic acid (DNA) from lambdaCI857st68h80dilv was used to detect isoleucine-valine (ilv) specific mRNA. A number of strains partially constitutive for the isoleucine-valine enzymes had levels of ilv mRNA 2 to 3-fold higher than the parent strain. Starvation for any of the branched-chain amino acids resulted in a 20 to 23-fold increase in ilv mRNA as compared to repressed levels. These differences were not due to altered growth rates or to changes in the stability of ilv mRNA. These data indicate that regulation of the isoleucine-valine enzymes by multivalent repression occurs mainly at the level of transcription. Kinetics of elongation of ilv mRNA after repression are consistent with the assumption that the mechanism of multivalent repression involves the prevention of further initiations by RNA polymerase.
Mol Gen Genet 1975 Jun 19
PMID:Transcriptional control of the isoleucine-valine messenger RNA's in E. coli K-12. 110 33

The DNA dependent synthesis of proteins was studied with a system composed of DNA, washed ribosomes, centrifuged (150,000 X g) bacterial extract from Escherichia coli and purified initiation factors IF-1 and IF-2. Synthesis of active enzymes encoded by the tryptophan (trp)-operon of E. coli was found to depend strongly on the addition of IF-3, with the same IF-3 dependency for all 5 gene-products of this operon, irrespective of the presence of the promotor proximal gene trpE. Synthesis of T7 RNA polymerase with T7 DNA as a template, however, was completely independent of the addition of IF-3. The same difference in IF-3 requirement was found when we compared the overall protein synthesis directed by these templates. This difference could be related to the effect of IF-3 on the formation of initiation complexes with the in vitro prepared mRNA: initiation complexes are readily formed with T7 mRNA also in the absence of IF-3, whereas the formation of these complexes with phi80trp mRNA almost completely depends on the presence of this factor.
Mol Gen Genet 1975 Sep 08
PMID:The role of IF-3 in the translation of T7- and phi80trp messenger RNA. 110 44

A mutant of Escherichia coli K12 is described in which sigma and alpha subunits of the DNA-dependent RNA polymerase (EC 2.7.7.6) are produced at the rates much higher than in the normal strain. The rate of synthesis for sigma subunit was found to be at least 10-times higher, though the rapid degradation of sigma polypeptides accompanied with the accelerated synthesis precludes accurate estimation of the extent of hyperproduction. The alpha subunit synthesis was about 5-times higher in this mutant than in the control, and excess alpha polypeptides produced were as stable as the bulk of protein under the conditions employed. Genetic analyses of the mutant by conjugation and by transduction with phage P1 revealed that at least three distinct but closely linked mutations are responsible for hyperproduction of the sigma subunit; one (sig-1) is located very close to rif, and the others (sig-2 and sig-3) at the argH-bfe and metB regions, respectively. The results further indicate that the accelerated synthesis of alpha subunit is due to a mutation also located at the metB region. The present finding suggests that the synthesis of sigma subunit is subject to a complex control that can be affected by a number of cellular processes. The possible involvement of the core polymerase in determining the rate of synthesis of sigma subunit is discussed.
Mol Gen Genet 1975 Nov 24
PMID:Hyperproduction of the sigma subunit of RNA polymerase in a mutant of Escherichia coli. 110 14

A soluble extract prepared from T7-infected E. coli is able to initiate DNA synthesis on an exogenous T7 DNA template. We have developed a fractionation procedure to resolve and identify the proteins required for T7 DNA synthesis. By this method we have purified the following T7 replication-related proteins (each greater than 50% pure as judged by sodium dodecyl sulfate gel electrophoresis): T7 DNA-binding protein (27,000 daltons), T7 RNA polymerase (105,000 daltons), T7 DNA polymerase (gene 5-protein, 85,000 daltons, plus host-factor), T7 DNA ligase (40,000 daltons), and T7 DNA-priming protein (65,000 daltons). The T7 DNA-priming protein, synthesized between 7.5 and 15 min following infection, was not detectable if the infecting phage carried an amber mutation in gene 4. Using an in vitro complementation assay which specifically measures the stimulation of DNA synthesis in an extract prepared from T7 gene 4-mutant infected cells, we have purified the DNA-priming protein about 2,000-fold. The purified priming protein preparations are essentially free of endonuclease, exonuclease, DNA ligase and DNA polymerase activity, but they do contain measurable DNA-dependent RNA synthetic acitvity. The enzyme is rapidly inactivated by heating to 46 degrees C and by treatment with N-ethylmalemide. In the presence of T7 DNA-binding protein and all four ribonucleoside triphosphates, the DNA-priming protein enables T7 DNA polymerase to initiate DNA synthesis on intact duplex T7 DNA. Closer studies of its enzymatic function as well as of the possible roles of the other proteins in the T7 replication system will be presented in the accompanying paper.
Mol Gen Genet 1975 Dec 01
PMID:Studies on bacteriophage T7 DNA synthesis in vitro. I. Resolution of the T7 replication system into its components. 110 17

Oligopyrimidines which contain 5'-hydroxymethylcytosine instead of cytosine were separated by thin layer chromatography. Using this method, the oligopyrimidine pattern of RNA polymerase binding sites, isolated from T4DNA, was evaluated quantitatively. The analysis shows that 1. the RNA polymerase binding sites on T4 DNA obtained under low salt conditions in absence of triphosphates, are A-T-rich as compared with total T4 DNA. 2. The A-T base pairs stand mainly in alternating position. On the average these sequences comprise more than half of the chain length of each binding site, which contains about 8 G-5'-HMC pairs. 3. The sites of binding and the sites of initiation do not show an identical base composition. 4. A mixture of at least 8 different binding istes is isolated under the conditions employed. This figure is in agreement with the number of distinct transcripts synthesized in nitro by E. coli RNA polymerase from T4 DNA. The overall length of these transcripts corresponds to approximately 9% of the T4 genome.
Mol Gen Genet 1975 Aug 05
PMID:RNA polymerase binding sites isolated from T4DNA: analysis of oligopyrimidine sequences constituting preinitiation and initiation complexes. 117 65

A photoactive nucleotide analogue of UTP, 5-azido-uridine 5'-triphosphate (5-N3UTP), has been demonstrated to interact with the RNA polymerase of the vesicular stomatitis virus (VSV) transcription complex. Kinetic studies indicated that 5-N3UTP served as an efficient replacement for UTP in in vitro polymerase reactions. The Km for the azido analogue was 27 microM and that of the natural substrate, UTP, was 7 microM. Photolysis of [gamma-32P]5-N3UTP in the presence of VSV transcription complexes resulted in selective radio-labelling of the L protein. This photolabelling was saturable with an apparent Kd of 28 microM. The L protein was protected from [gamma-32P]5-N3UTP-mediated photolabelling by competing natural substrates (UTP, CTP, ATP, GTP). The stoichiometry of photoprobe incorporation into the transcription complex was close to unity with respect to the L protein. These data provide evidence that the nucleotide-binding domain of the VSV RNA polymerase contains amino acid residues of the L protein.
J Gen Virol 1992 Jan
PMID:The L protein of vesicular stomatitis virus transcription complexes is specifically photolabelled by 5-azido-uridine 5'-triphosphate, an analogue of the RNA polymerase substrate uridine 5'-triphosphate. 130 62

A photoaffinity analogue of ATP, 8-azido-adenosine 5'-triphosphate (8-N3ATP), was used to probe ATP-binding sites in native transcription complexes of vesicular stomatitis virus (VSV) (New Jersey serotype). The analogue was found to be a substrate for a serine/threonine protein kinase that phosphorylated both the NS and L proteins of native complexes. The analogue failed to interact with the RNA polymerase, another ATP-utilizing activity associated with the transcription complex. Kinetic analyses of both ATP and 8-N3ATP utilization by the protein kinase yielded biphasic saturation curves. Photolysis of 8-N3ATP in the presence of VSV transcription complexes resulted in selective labelling of the L protein. The photolabelling of L was saturable and apparently biphasic. Photolabelling of the L protein was significantly reduced by competition with ATP whereas other nucleoside triphosphates (GTP, UTP and CTP) were ineffective competitors. The stoichiometry of photolabelling was 0.2 at 10 microM-8N3ATP and 1.3 at 100 microM-ATP. These data provide chemical evidence for a virus-encoded serine/threonine protein kinase which resides on the L protein.
J Gen Virol 1992 Jan
PMID:Identification and characterization of serine/threonine protein kinase activity intrinsic to the L protein of vesicular stomatitis virus New Jersey. 130 63

The gene (cytA) coding for the 27 kDa polypeptide of the Bacillus thuringiensis var. israelensis mosquito larvicidal delta-endotoxin, was cloned into a plasmid containing the T7 bacteriophage promoter. The plasmid was used to transform an Escherichia coli strain containing the T7 RNA polymerase gene 1, under the control of lacP. Loss of colony-forming ability without substantial lysis, associated with immediate inhibition of DNA synthesis, was observed after induction of transformed cells. The cytA gene product may kill E. coli cells by disrupting their chromosome replicating apparatus.
Mol Gen Genet 1992 Mar
PMID:Sensitivity to plating of Escherichia coli cells expressing the cryA gene from Bacillus thuringiensis var. israelensis. 131 46

The genome of Epstein-Barr virus (EBV) codes for two non-translated small RNA molecules, EBER 1 and 2. We found that both EBERs are expressed in the major EBV-carrying cell types, group I and III Burkitt's lymphoma (BL) cell lines, lymphoblastoid cell lines (LCLs) and in two nude mouse-passaged nasopharyngeal carcinoma (NPC) tumours. The relative amount of EBER 1 and EBER 2 varied in different host cells but did not correlate with the cellular phenotype. The EBER coding and flanking sequences were predominantly hypomethylated at HpaII sites not only in LCLs which usually carry hypomethylated EBV genomes but also in BL and NPC cell lines harbouring EBV episomes that are highly methylated in other regions. Thus, the EBER transcription units, actively transcribed by RNA polymerase III in the major EBV-carrying cell types, represent a methylation-free region in the EBV genome similarly to regulatory sequences of the latent membrane protein gene when the latter is transcribed by RNA polymerase II.
J Gen Virol 1992 Jul
PMID:RNA polymerase III-transcribed EBER 1 and 2 transcription units are expressed and hypomethylated in the major Epstein-Barr virus-carrying cell types. 132 Dec 9


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