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)

An RNA polymerase activity has been demonstrated in purified rabies virions. Efficiency of the reaction is low since the rate of incorporation was equal to 3 to 5 pmol of uridine per hour, per mg of protein. As with other mammalian rhabdoviruses the optimal temperature was 31 degrees C. Unlike vesicular stomatitis virus, manganese could be substituted for magnesium as a divalent cation, at an optimum concentration of 10 to 20 mM.
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PMID:An RNA polymerase activity in purified rabies virions. 2 77

Although many researchers have reported that RNA synthesis in the ovary is enhanced by gonadotropin treatment, there are only a few papers concerning the character of newly synthesized RNA after gonadotropin treatment. In this paper, the RNA synthesized in the ovary of immature rats after HCG treatment was qualitatively studied. Immature female Sprague-Dawley rats were administered with 0.3 mc per rat of 3H-uridine at a certain time interval after injection of HCG (10 iu/rat) and the ovaries were subsequently isolated after 15, 30 or 60 minutes. RNA was extracted from the homogenate of the ovaries according to the hot phenol method after Scherrer and Darnell. The 3H-RNA thus extracted was treated with electrophoretically purified DNase to break down and remove DNA that mingled with it. The RNA solution ultimately obtained was analysed on a 3-20% sucrose gradient. The different fractions thus separated were then subjected to measurement of radioactivity and optical density at 260 mmug. The RNA extracted from the ovary of immature untreated rat labeled with 3H-uridine for 15 minutes showed a flat pattern of radioactivity from the top to the bottom fractions with low radioactivity. Otherwise, when labeled for one hour, the RNA showed a pattern of radioactivity like those of optical density at 260 mumu with peaks of r-RNAs and t-RNA. When the ovary was pulse-labeled with 3H-uridine for 15 minutes starting 2 hours after injection of HCG, the RNA with a large S value was synthesized and the pattern of variation in radioactivity was that of rising near the bottom fraction and declining with access to the top fraction. The results obtained by labeling for 15 minutes starting 40 hours after PMS administration were similar to those obtained in immature untreated rats. The patterns of radioactivity in RNA obtained by the labeling for 15 minutes starting 2 hours after HCG and 42 hours after PMS were similar to those starting 2 hours after only HCG injection. The patterns of radioactivity became similar to those of optical density at 260 mmu, when the ovaries were labeled for 30 or 60 minutes. From these results, it was suggested that the newly synthesized RNA 2 hours after HCG was constructed from m-RMA with rapid turn over and precursors of r-RNAs and t-RNA. This RNA synthesis was blocked by pretreatment with actinomycin but not by cycloheximide. From these results, it was suggested that enhancement in RNA polymerase activity or change in template capacity of DNA which would have an effect on RNA synthesis was not based on newly synthesized protein.
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PMID:[Studies on the RNA synthesized in the ovary of immature rats after HCG administration (author's transl)]. 5 Sep 55

A long-term cell culture of human glioblastoma was investigated microscopically, virologically, and biochemically. Reverse transcriptase activity was detected in cultured human glioblastoma cells. 3H uridine was incorporated into particles of buoyant density at 1.07 g/ml (Ficoll) which is equal to that of Oncorna virus particles, but 3H thymidine was not incorporated at all. Furthermore, reverse transcriptase activity was also demonstrated with the particles, suggesting that the cultured human glioblastoma cells were producing type C Oncorna virus. Ultrastructural observations of cell culture of glioblastoma showed type C virus particles in cisternae and culture medium. Budding of the virus was also seen on the surface of the cell. The mean diameter of the particles was approximately 100 nm. Ca. 1.1 nm of spikes protruded from the envelope. Both types of virions were observed, i.e. the doughnut-shaped type form and the solid circular form.
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PMID:Type C particles in culture of human glioblastoma cells. 8 68

A class of rifampin-resistant (rfm) mutations of Bacillus subtilis suppresses the temperature-sensitive sporulation of a fusidic acid-resistant mutant. FUS426, which has an altered elongation factor G. The rfm mutation suppressed only the sporulation defect caused by the elongation factor G mutation, but could not suppress other types of induced sporulation defects. Genetic and biochemical analyses showed that the sporulation suppression by the rfm mutation was caused by a single mutation in RNA polymerase. After the early sporulation phase, the apparent rate of RNA synthesis of FUS426, measured by [3H]uracil or [3H]uridine incorporation into RNA, became lower than that of the wild-type strain, and this decrease was reversed by the rfm mutation. However, when the total rate of RNA synthesis of FUS426 was calculated by measuring the specific activity of [3H]UTP and [3H]CTP, it was higher than that of the rfm mutant, RIF122FUS426. The possible mechanism of the functional interaction between elongation factor G and RNA polymerase during sporulation is discussed.
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PMID:Suppression of temperature-sensitive sporulation of a Bacillus subtilis elongation factor G mutant by RNA polymerase mutations. 10 38

The RNA polymerase in cells infected with three group I mutants of vesicular stomatitis virus has been examined. Mouse L cells were incubated at the permissive temperature (30 degrees C) for a few hours after infection to allow the development of secondary transcription. The temperature dependence of the secondary transcription system was determined from the incorporation of labelled uridine, in the presence of cycloheximide, at 30 and at 38 degrees C, the later temperature being non-permissive for viral replication. In cells infected with mutants W14, W28, and G11 at a low multiplicity (20 PFU/cells) secondary transcriptase activity was markedly temperature-sensitive after 3 and 5 h of infection at 30 degrees C. At a high multiplicity of infection (1000 PFU/cell) cells infected with W28 showed considerable RNA synthesis at 38 degrees C after 3 h at 30 degrees C. RNA synthesis was also observed in W28-infected cells in which protein synthesis was allowed to continue after the shift from 30 to 38 degrees C. In the latter two cases the RNA synthesized contained 12-18S species but little or no 30S mRNA.
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PMID:Temperature-sensitive mutants of vesicular stomatitis virus: viral RNA synthesis in cells infected with mutants belonging to complementation group I. 18 5

Synthesis of ribonucleic acid (RNA) by the deoxyribonucleic acid-dependent RNA polymerase of Coxiella burnetii required adenosine, uridine, guanosine, and cytidine 5'-triphosphates. Cell-free preparations of this obligate intracellular procaryotic parasite had competence to phosphorylate ribonucleoside mono- and diphosphates in the presence of exogenous adenosine and guanosine 5'-triphosphates to the corresponding di- and triphosphates. C. burnetii contained about 2 nmol of adenosine 5'-triphosphate per mg of protein, which could serve as a approximately P donor for in vivo synthesis of nucleoside triphosphates. The latter were then used as substrates in the synthesis of RNA in a coordinated metabolic system with C. burnetii RNA polymerase. It is suggested that during infection the rickettsiae might obtain the nucleotides necessary for RNA synthesis from the vacuoles in which C. burnetii proliferates.
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PMID:Synthesis of ribonucleotides and their participation in ribonucleic acid synthesis by Coxiella burnetii. 20 Jun 3

An important model for the transcription of the late (L) strand of simian virus 40 DNA is that, late after infection of permissive monkey cells, the RNA polymerase makes a complete transcript of the L DNA strand before terminating transcription. The purpose of the current work was to test a prediction of this model, namely, that the rate of synthesis of all RNA sequences from the L DNA strand should be equal. About one-half of the L DNA strand is transcribed into late mRNA sequences and the other half into late dRNA sequences, which do not leave the nucleus. Using glucosamine to reduce the size of the intracellular UTP pool before and after a pulse-label with radioactive uridine, a pulse-chase experiment was performed to determine the half-lives of these sequences. The half-life of the late dRNA sequences was determined to be 4 min. The late mRNA sequences were degraded more slowly, on the average, than the late dRNA sequences. In a parallel experiment with similarly treated cells, it was shown that after a 2-min label with radioactive uridine there was only 0.2 times as much radioactivity in the late dRNA sequences as in the late mRNA sequences in the total cellular RNA population. The results could be combined to calculate that the rate of synthesis of the late dRNA sequences was at most 0.3 times that of the late mRNA sequences. Consequently they provide strong evidence that when the RNA polymerase transcribes the late mRNA sequences, it usually terminates transcription before all the late dRNA sequences are transcribed.
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PMID:Evidence that the RNA polymerase usually does not make a complete transcript of the late strand of simian virus 40 DNA. 21 41

The in vitro transcription of viral specific DNA sequences in nuclei and chromatin isolated from mouse cells chronically infected with Moloney murine leukemia virus (Mo-MuLV) has been studied. The in vitro RNA synthesized by Escherichia coli RNA polymerase has been isolated by sulfhydryl affinity column following reaction in the presence of 5-mercuriuridine triphosphate. By comparison of the Crt curves of the in vitro RNA with that of 70S viral RNA, the content of viral sequences is found to be 1.3% in nuclei product and 0.24% in chromatin product which is lower than the 2.5% found in chromatin associated RNA. This latter value, however, is very close to the in vivo viral RNA content in pulse-labeled [3H]RNA of the infected cells. Unexpectedly, it is observed that over 20% of the chromatin associated RNA prelabeled in vivo with [5-3H]uridine is elongated and tagged with Hg atoms during RNA synthesis catalyzed by the exogenous E. coli RNA polymerase in the presence of Hg-UTP. The elongation reaction is dependent on the presence of all four nucleotide triphosphates and appears to be due to E. coli RNA polymerase per se. It is suggested that most of the viral specific sequences observed in the in vitro RNA products are very likely initiated and derived from the chromatin associated species. The implication of the present findings for in vitro RNA synthesis in nuclei and chromatin as related to regulation of gene expression is discussed.
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PMID:In vitro transcription of Moloney leukemia virus genes in infected cell nuclei and chromatin: elongation of chromatin associated ribonucleic acid by Escherichia coli ribonucleic acid polymerase. 32 7

Synthetic DNA templates were transcribed by Escherichia coli RNA polymerase using nucleoside 5'-[gamma-S]triphosphates as one of the nucleotide substrates. Substitution of the thiol analogues for the normal nucleotides had no effect on the rate of RNA synthesis. RNA synthesized with either adenosine 5'-[gamma-S]triphosphate or guanosine 5'-[gamma-S]triphosphate was isolated with high efficiency on mercury-agarose columns prepared by activation with low concentrations of cyanogen bromide. Sulfur was shown to be incorporated at the 5' end of RNA by identification of the tetraphosphate HSpppA32p liberated after alkaline hydrolysis of HS(A-32pU)n (alternating copolymer synthesized by the action of E. coli RNA polymerase on d(A-T)n-d(A-T)n with adenosine 5'-[gamma-S]triphosphate and uridine 5'-[alpha-32P]triphosphate as substrates). Transcripts elongated but not initiated with these thiol analogues did not bind to the affinity column. This technique provides an extremely sensitive assay for RNA synthesis initiation in vitro, since initiated transcripts containing radiolabel throught the entire transcript can be isolated.
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PMID:Incorporation of purine nucleoside 5'-[gamma-S]triphosphates as affinity probes for initiation of RNA synthesis in vitro. 33 43

3'(2')-O-acyl derivatives of the uridine triphosphate were synthesized. Acyl residues contained fluorescent dye; fluoresceine or rodamine C. Optical properties and stability of UTP analogues were studied. Their ability to serve as the substrates for calf thymus terminal deoxyribonucleotidyl transferase and E. coli RNA polymerase was also examined. It was shown that both enzymes were able to use tested analogues as substrates. Incorporation of the analogues into nascent RNA and DNA chains inhibited the synthetic reaction because of primer inactivation. The rate of the incorporation of the analogues showed an exponential time dependence
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PMID:[Addition of the fluorescent label to the 3'-OH end of DNA and the 3'-OH end of nascent RNA]. 37 5


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