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)

High-molecular-weight native mouse DNA was transcribed with Escherichia coli RNA polymerase under low salt conditions, and the nature of the DNA sequences transcribed determined by molecular hybridization. The results indicated that E. coli RNA polymerase does not transcribe the sequences in native mouse DNA randomly under these conditions. First, hybridization with a large excess of mouse DNA showed that no more than 5% of the RNA synthesized had been transcribed from repeated sequences in the DNA. Second, hybridization with tracer amounts of labelled non-repeated mouse DNA indicated that the bulk of the RNA had been transcribed from less than 1% of the non-repeated sequences and only about 10% had been transcribed from a further 25% of these sequences; the remaining non-repeated sequences in the DNA, amounting to 50% of the genome, were not represented in the RNA synthesized in vitro to any detectable extent. Third, the proportion (40%) of complementary DNA transcribed from mouse-liver nuclear polyadenylated RNA which hybridized with the RNA synthesized in vitro was significantly greater than would have been expected if transcription had been random. The data have also been interpreted as indicating the presence of two types of initiation site for E. coli RNA polymerase in the non-repeated sequences in mouse DNA. The frequencies of their occurrence have been calculated to be one per 150 000 base-pairs and one per 500 base-pairs, respectively.
Biochim Biophys Acta 1976 Dec 13
PMID:Characterization of the RNA transcribed in vitro from native mammalian DNA by Escherichia coli RNA polymerase. 79 29

Thermoinduction of cells of E. coli carrying prophage lambdacI857 within the bfe gene brings about not only "escape synthesis" of core subunits of the DNA-dependent RNA polymerase (RNA nucleotidyltransferase, nucleosidetriphosphate:RNA nucleotidyltransferase, EC 2-7-7-6), but also a striking stimulation of sigma factor synthesis. The latter phenomenon, termed sigma induction, is generally observed after lambda phage infection or prophage induction. A series of experiments with various bacterial and phage strains led us to conclude that the N gene product of lambda is directly involved to the sigma induction. These and other results obtained with mutants defective in transcription termination factor rho suggest the involvement of a rho-sensitive site in the control of sigma gene expression in E. coli.
Proc Natl Acad Sci U S A 1976 Dec
PMID:Induction of sigma factor synthesis in Escherichia coli by the N gene product of bacteriophage lambda. 79 77

The cleavage sites in the early promoter region of coliphage T7 have been mapped for four restriction enzymes. They are, from the left end in base pairs, 1100 and 740 for Hinf; 680, 320, 530, 240, 77, and 67 for Hind II; 620 and 530 for Hpa II; 790 for Alu I. The nucleotide sequence between the Hind II site at 680 base pairs from the left end and the Hinf site at 740 base pairs from the left end has been determined, from which the start point of the promoter A3 is located at 720 base pairs from the left end. The start points of the other two major promoters A1 and A2 are deduced to be at 460 and 580 base pairs from the left end, respectively, from the chain lengths of the in vitro transcripts off the 1100 base-pairs long Hinf fragment. Similar to the sequences of a pL and pR promotors of phage lambda and a sequence in Simian Virus 40 used by Escherichia coli RNA polymerase as a promotor, the sequence of the A3 promotor of T7 also has a Hind II restriction site approximately 30 base pairs upstream to the start point of RNA synthesis. No such Hind II sites exist, however, for the A1 and A2 promoters. Experiments on the protection of some of the restriction sites on the 1100 base-pairs-long Hinf fragment by RNA polymerase binding support the electron microscopic observations of others that, in addition to the three sites A1, A2 and A3, there is at least a fourth site at which E. coli RNA polymerase can bind strongly. In addition to the Hind II site at 680 base pairs from the left end and the Hinf site at 740 base pairs from the left end, which are presumably protected by the binding of a single RNA polymerase at the A3 site, the Hind II site at 240 base pairs from the left end is also protected at a level of 5 polymerase molecules/DNA fragment. The possible existence of several minor promotor sites in the early promotor region, in addition to the three major promotor sites, is discussed.
Biochemistry 1976 Dec 28
PMID:Physicochomecial studies on interactions between DNA and RNA polymerase. Isolation and mapping of a T7 DNA fragment containing the early promoters for Escherichia coli RNA polymerase. 79 61

1. Partially diploid strains of Escherichia coli containing both rifampicin-sensitive and rifampicin-resistant RNA polymerase are, in general, sensitive to the drug: of the two copies of the rpoB gene present in such strains, that which codes for sensitive enzyme is dominant. 2. RNA polymerase purified from a normal sensitive strain of E. coli, and inactivated by rifampicin, can "blockade" bacteriophage T7 DNA in vitro, inhibiting its transcription by drug-resistant enzyme molecules. 3. A mutation, rcs-40, reverses the normal dominance relationship in vivo, without detectably affecting the concentrations of resistant and sensitive RNA polymerase in the diploid cell. I show that rcs-40 is closely linked to the rpoB gene which codes for the rifampicin-sensitive enzyme. 4. Rifampicin-sensitive RNA polymerase purified from E. coli rcs-40, although indistinguishable from the normal enzyme by many criteria, is significantly less efficient in the production of drug-dependent DNA blockade.
Eur J Biochem 1976 Dec
PMID:DNA blockade by rifampicin-inactivated Escherichia coli RNA polymerase, and its amelioration by a specific mutation. 79 62

An inhibitor of the Escherichia coli RNA polymerase has been isolated from E. coli and has been partially characterized. The inhibitor, a polypeptide of molecular weight 70000, acts to shut off RNA synthesis at about the time that the first round of RNA synthesis is over, preventing any further RNA synthesis. The inhibitor apparently does not recognize specific termination sequences in the DNA template, since it works equally well with double-stranded DNA, single-stranded DNA and poly[d(A-T)] as templates for RNA synthesis, and because the RNA molecules synthesized from T7 DNA appear to be terminated at the same site either in the presence or absence of the inhibitor. Several experiments indirectly indicate that the inhibitor may reversibly bind to the RNA polymerase at the termination step, in a ratio of approximately one inhibitor molecule per polymerase molecule.
Eur J Biochem 1976 Dec
PMID:Isolation and properties of an inhibitor of Escherichia coli RNA polymerase. 79 63

The effects of a partial restriction of valyl-tRNA aminoacylation on the synthesis of aminoacyl-tRNA synthetases, ribosomal proteins, and other translation and transcription proteins were examined in otherwise isogenic stringent (relA+) and relaxed (relA1) derivatives of E. coli B. The synthesis of individual ribosomal proteins, elongation factor G, and to a lesser extent elongation factors Tu and Ts, and the valyl- and arginyl-tRNA synthetases was found to be subject to the influence of the stringent control system. The synthesis of the alpha and beta subunits of RNA polymerase and several of the aminoacyl-tRNA synthetases, in contrast, is either not subject to the influence of the stringent control system, or is subject to additional regulatory constraints.
Mol Gen Genet 1976 Dec 22
PMID:The effects of the relA gene on the synthesis of aminoacyl-tRNA synthetases and other transcription and translation proteins in Escherichia coli A. 79 47

The activity of dihydrodipicolinate synthase increased late in sporulation in Bacillus subtilis. Mutants blocked at several stages of sporulation due to having an altered ribonucleic acid polymerase failed to exhibit this increase.
J Bacteriol 1975 Dec
PMID:Bacterial sporulation and regulation of dihydrodipicolinate synthase in ribonucleic acid polymerase mutants of Bacillus subtilis. 81 51

A new form of DNA-dependent RNA polymerase termed enzyme III has been purified from sporulating cells of Bacillus subtilis. In addition to the subunits of core RNA polymerase (beta', beta, alpha, and omega), enzyme III contains sporulation-specific polypeptides of 85,000 (P85) and 27,000 (P27) daltons. P85 corresponds to an RNA polymerase-binding protein previously identified by precipitation of RNA polymerase from crude extracts of sporulating cells with antibody directed against core enzyme. Both P85 and P27 co-purified with RNA polymerase highly purified by gel filtration, DEAE-cellulose chromatography, phosphocellulose chromatography, and glycerol gradient centrifugation. Enzyme III bound more tightly to phosphocellulose and sedimented more rapidly during zone centrifugation than did RNA polymerase lacking the sporulation polypeptides. RNA polymerase containing P85 and P27 transcribed B. subtilis DNA about 4.5 times more actively than did core RNA polymerase, although both enzymes exhibited similar activities with poly(dA-dT) and phage phie DNA as templates. Enzyme III and core RNA polymerase also differed in their response to increasing concentrations of Mg2+ and KCl.
J Biol Chem 1975 Dec 25
PMID:RNA polymerase from sporulating Bacillus subtilis. Purification and properties of a modified form of the enzyme containing two sporulation polypeptides. 81 62

A purification procedure is described by which we obtained DNA-dependent RNA polymerase B (or II) from third-instar larvae of Drosophila melanogaster in essentially pure form. The enzyme is similar to the analogous polymerases from other eukaryotes in its enzymic and structural properties. It preferentially transcribes DNAs containing single-stranded regions, and it is inhibited by low amounts of the toxin alpha-amanitin; 50% inhibition occurs at an alpha-amanitin concentration of 0.03 mug/ml. Dodecylsulfate-polyacrylamide gel electrophoresis resolves the purified Drosophila polymerase B into ten polypeptides with molecular weights as follows: 1 (174000), 2 (137000), 3 (34000), 4 (22000), 5 (18000), 6 and 7 (16000), 8 (15000), and 9 and 10 (less than 15000). The relative amounts of polypeptides 1-4 were constant at molar ratios of approximately 1:1:1:2 in different preparations of the enzyme, while the amounts of polypeptides 5-10 showed more variation. An antiserum directed against the Drosophila RNA polymerase B inhibited the activity in vitro of the B enzymes from Drosophila, yeast, and calf thymus. However, only the Drosophila enzyme gave a precipitin reaction with the antiserum. When the antiserum was added to Drosophila RNA polymerase B at different stages of the purification, the resulting precipitates were found to contain nearly constant proportions of seven of the ten polypeptides present in the purified enzyme.
Eur J Biochem 1975 Dec 01
PMID:RNA polymerase B from Drosophila melanogaster larvae. Purification and partial characterization. 81 97

RNA polymerase (nucleosidetriphosphate: RNA nucleotidyltransferase, EC 2.7.7.6) was purified from rifampicin-resistant Bacillus subtilis, from both uninfected cells and cells infected with bacteriophage SP01. The enzyme from infected cells lacked all traces of the sigma subunit, contained several polypeptides absent from the enzyme made in uninfected cells, and had an altered template specificity in a transcription assay. A cell-free protein synthesizing system from Escherichia coli, when poisoned with rifampicin, was completely dependent on addition of either of these RNA polymerase preparations for DNA-dependent protein synthesis. Under these conditions, the SP01-modified RNA polymerase preferentially stimulated the synthesis of functional mRNA for the phage enzyme dCMP deaminase (deoxycytidylate aminohydrolase, EC 3.5.4.12), whereas unmodified B. subtilis RNA polymerase could stimulate synthesis of this mRNA in small quantity and only after prolonged incubation. This mRNA belongs to a class of phage transcripts (m) which cannot be transcribed in vivo in the absence of phage-specific protein synthesis.
Proc Natl Acad Sci U S A 1975 Dec
PMID:Synthesis of specific functional messenger RNA in vitro by phage-SP01-modified RNA polymerase of Bacillus subtilis. 81 16


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