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)

Nuclear DNA-dependent RNA polymerases were isolated from Ehrlich ascites carcinoma, TA3 ascites adenocarcinoma, and mouse liver and tested for inhibition by glycerol. The results confirm the finding of Smith and Duerksen ((1975) Biochem. Biophys. Res. Commun. 67, 916-923) that glycerol may inhibit nuclear RNA polymerase II, but because different grades of glycerol inhibited mouse liver RNA polymerase IIa to different extents, it is suggested that an inhibitory contaminant is present. RNA polymerases IIa and IIb from the two tumors and mouse liver were proportionately inhibited by A.C.S. reagent-grade glycerol at concentrations above 10%. RNA polymerase Ia from liver and the TA3 tumor was not inhibited by any concentration of glycerol tested (2-32.3%), but RNA polymerase Ia from Ehrlich carcinoma was inhibited by glycerol concentrations above 16%.
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PMID:Inhibition of nuclear DNA-dependent RNA polymerases from mouse ascites tumors and liver by glycerol. 91 4

The nonhistone proteins of Ehrlich ascites tumor chromatin have been separated into a loosely bound and two tightly bound protein fractions by sequential extraction of chromatin with 0.35 M NaCl and 2 M NaCl:5 M urea. The nonhistone proteins thus obtained were examined for their chemical composition and distribution of DNA polymerase, RNA polymerase, and protein kinase activities. In addition, the effect of these nonhistone proteins on transcription of DNA in vitro has been determined. The results indicate that these nonhistone proteins, fractionated on the basis of their extractability, exhibit varied compositional characteristics and play different functional roles in the synthesis of DNA and RNA and in the possible control of gene activity.
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PMID:A comparison of the loosely bound and tightly bound nonhistone proteins from Ehrlich ascites tumor chromatin. 97 79

A factor stimulating RNA polymerase II from Ehrlich ascites tumor cells was purified. The final preparation appeared almost homogeneous on sodium dodecyl sulfate-polyacrylamide gel electrophoresis and had a molecular weight of 38 000. The endonuclease activity of about 10 mug of purified factor, if any was well below the 10(-5) mug equivalent of pancreatic deoxyribonuclease, indicating that the stimulation of RNA synthesis by this factor was not due to contaminating endonuclease. This factor specifically stimulated RNA polymerase II on native DNA as template and did not affect RNA polymerase I at all. The molecular size of RNA synthesized in the presence of this factor increased markedly compared with that synthetized by RNA polymerase II alone.
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PMID:Purification of a factor from Ehrlich ascites tumor cells specifically stimulating RNA polymerase II. 99 Feb 65

Two different forms of DNA-dependent RNA polymerase have been solubilized and purified from nuclei of Ehrlich ascites tumor cells. The purification procedure involves ammonium sulfate precipitation and gel filtration on Sephadex G-25. The separation of A and B activities is achieved by chromatography on DEAE-cellulose. Nuclei are prepared from cells, sensitive or resistant to daunorubicin. RNA polymerases A and B have an absolute requirement of divalent cations for activity. Native DNAs are better templates than heat-denatured DNAs for RNA polymerase A. On the contrary heat-denatured DNA is more transcribed than the native one by RNA polymerase B. The low level of transcription of total and nucleolar ascites DNAs is due to the DNA, the same results being obtained with ascites and calf thymus RNA polymerases A and B. The inhibitory action of daunorubicin on RNA polymerases A and B from Ehrlich ascites tumor cells has been studied in vitro. The same results are obtained with enzymes extracted from sensitive or resistant cells. Daunorubicin does not inhibit the binding of RNA polymerases to the DNA template, but prevents the transformation of the DNA-daunorubicin-RNA-polymerase unstable complex into the highly stable one. This inactive ternary complex has a dissociation rate faster than the stable complex formed without daunorubicin. The size of the RNA synthesized in the presence or absence of daunorubicin is the same.
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PMID:Daunorubicin inhibition of DNA-dependent RNA polymerases from Ehrlich ascites tumor cells. 99 57

Rhodium(II) acetate, propionate, and butyrate showed a considerable variation in their antitumor activity against Ehrlich ascites tumor cells in mice, with the butyrate complex being the most active. The three complexes markedly inhibited DNA synthesis of Ehrlich ascites tumor cells in vivo. Rhodium (II) butyrate was the most potent inhibitor followed by the propionate complex. One hour after administration, rhodium(II) propionate and butyrate induce more uridine-5-3H incorporation into RNA than is seen in the controls. Equilibrium dialysis studied showed that rhodium(II) acetate-1-14C binds to single stranded DNA, poly-A, ribonuclease A, and bovine serum albumin but not to highly polymerized native calf thymus DNA, poly-G, or poly-C. In these cases binding occurred at the two axial positions of rhodium(II) acetate to a nitrogen donor in the ligands. The formation constants of the rhodium(II) acetate and propionate complexes with 5'-adenosine monophosphate were determined. The rhodium(II) propionate complex was more stable. Sedimentation and viscosity measurements of poly-A and poly-A/rhodium(II) acetate complexes indicate a high degree of intramolecular crosslinking in the rhodium(II) acetate/poly-A complex. The rhodium(II) carboxylate complexes were also found to be potent inhibitors of purified DNA polymerase I and RNA polymerase from Escherichia coli.
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PMID:Interaction of Rhodium(II) carboxylates with molecules of biologic importance. 110 39

The loosely bound chromatin proteins of Ehrlich ascites hyperdiploid cells have been prepared by extraction of chromatin with 0.35 M NaCl. Sodium dodecyl sulfate gel electrophoresis of the 0.35 M NaCl-soluble chromatin proteins reveals high heterogeneity with a molecular weight range of 10,000 to 170,000. The 0.35 M NaCl-soluble chromatin proteins contain many components similar to the more tightly bound non-histone chromatin proteins complex with the loosely bound chromatin proteins by gradient dialysis, the inhibitory effect of histones on transcription of DNA in vitro was reduced. The reconstituted complex manifested a level of template activity similar to that of native chromatin as measured in an Ehrlich ascites tumor RNA polymerase reaction. The loosely bound chromatin proteins contain RNA as well as phosphoproteins. Phenol extraction or DNA affinity chromatography of these proteins yielded fractions enhanced 25- to 30-fold in phosphorus which were capable of stimulating DNA-templated RNA synthesis in vitro. The stimulation of transcription from DNA was template-specific, effective only with a DNA template prepared from Ehrlich ascites tumor, but not from rat liver, calf thymus, or chicken erythrocytes. In addition, the stimulatory effect of the specific DNA-binding proteins appears to be RNA polymerase-specific, the stimulation being manifested with Ehrlich ascites tumor nucleoplasmic RNA polymerase and not with Micrococcus luteus RNA polymerase. Thus, the loosely bound chromosomal proteins from Ehrlich ascites tumor contain a fraction that specifically binds to Ehrlich ascites tumor DNA and exhibits a template- and RNA polymerase-specific stimulatory effect on transcription from DNA.
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PMID:Study of the loosely bound non-histone chromatin proteins. Stimulation of deoxyribonucleic acid-templated ribonucleic acid synthesis by a specific deoxyribonucleic acid-binding phosphoprotein fraction. 111 17

Nuclear RNA polymerase activity was studied in homotransplanted rat glial tumors where the primary tumor was produced by transplacental injection of ethylnitrosourea. Alpha amanitin, cycloheximide, and rifampicin were tested as inhibitors of this activity. Alpha amanitin significantly inhibited RNA polymerase activity in all tumors. This indicated that the major nuclear RNA polymerase activity seen in vitro in the tumor nuclei was RNA polymerase II. This is similar to the activity seen in normal glial nuclei. Cycloheximide and rifampicin which have no effect on RNA polymerase activity in normal glial nuclei inhibited about 20% of the polymerase activity in three of the tumors. The size and multiplicity of the nucleoli in these tumor cells suggests that RNA polymerase I could account for the activity which is inhibited by cycloheximide.
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PMID:RNA polymerase activity in homotransplanted rat brain tumors initially induced by ethylnitrosourea. 114 4

DNA-dependent RNA polymerase II was purified from the mouse plasmacytoma, MOPC 315. Soluble enzyme was obtained from a nucleoplasmic fraction and subjected to chromatography on phosphocellulose, DEAE-cellulose, and DEAE-Sephadex ion exchange resins and was subjected to sedimentation in sucrose density gradients. A chromatographically homogeneous enzyme was obtained which was purified about 25,000-fold relative to whole cell extracts and which had a specific activity (on native DNA) similar to those reported for other purified eukaryotic class II RNA polymerase preparations. Analysis of purified RNA polymerase II by polyacrylamide gel electrophoresis under nondenaturing conditions revealed three protein bands, designated II-O, II-A, and II-B in order of electrophoretic mobility. The subunit compositions of these nondenatured bands were subsequently analyzed by electrophoresis under denaturing conditions. Each enzyme II form contained subunits with molecular weights of 140,000 (II-c), 41,000 (II-d), 30,000 (II-e), 25,000 (II-f), 22,000 (II-g), 20,000 (II-h), and 16,000 (II-i). Molar ratios were unity for all subunits except subunit II-h which had a molar ratio of 2. Each enzyme form was distinguished by its highest molecular weight subunit. II-O contained subunit II-o (molecular weight 240,000), II-A contained subunit II-a (molecular weight 205,000), and II-B contained subunit II-b (molecular weight 170,000). Total molecular weights for II-O, II-A, and II-B were calculated as 554,000, 519,000, and 484,000, respectively. In addition, the number of RNA polymerase II molecules per MOPC 315 tumor cell was calculated to be about 5 times 10-4.
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PMID:Purification and subunit structure of deoxyribonucleic acid-dependent ribonucleic acid polymerase II from the mouse plasmacytoma, MOPC 315. 116 91

DNA-dependent RNA polymerase was solubilized from nuclei of Ehrlich ascites carcinoma (EAC) cells by sonic disruption in the presence of 0.3 M (NH4)2 SO4, and the multiple RNA polymerases were separated by chromatography on DEAE-Sephadex A-25. Elution with a nine-step gradient of (NH4)2 SO4 yielded five peaks of activity designated RNA polymerases Ia, Ib, IIa, IIb, and III, of which IIb was the most prominent. Linear-gradient elusion also yielded five peaks of the same designation, but Ia and Ib, as well as IIa and IIb, were not well separated. IIa and IIb were inhibited completely by 0.1 mug alpha-amanitin/ml, whereas the other forms were not. EAC RNA polymerases Ia, Ib, IIa, and IIb possessed Mg2+ ion, Mn2+ ion, and (NH4)2 SO4 optima, molecular weights, and thermal sensitivities similar to those reported for other mammalian DNA-dependent RNA polymerases. As measured by relative ribonucleoside monophosphate incorporation, with native calf thymus DNA template, EAC RNA polymerases Ia and Ib synthesized ribosomal RNA-like products, whereas forms IIa, IIb, and the parent enzyme mixture synthesized compounds that were more similar to DNA. No species specificity was found for DNA templates, and denatured DNA was consistently preferred to the native template by RNA polymerases IIa and IIb; the two kinds of template were about equally efficient for RNA polymerases Ia and Ib. Although EAC RNA polymerases Ia, IIa, and IIb were inhibited by daunomycin, form IIa was preferentially affected. 3',5'-Cyclic AMP, 3',5'-Cyclic GMP, and gibberellic acid, implicated as RNA polymerase regulators in other systems, were generally ineffective. The levels of nuclear RNA polymerase activities, per mg DNA, of 3 mouse ascites tumors (EAC, 6C3HED lymphosarcoma, and TA3 adenocarcinoma) were compared with those from 3 normal mouse tissues (kidney, liver, and spleen). On the average, the tumor cell nuclei contained (per mg of DNA) 8.9, 1.5, 2.7, 20.0, and 3.8 times the activities of RNA polymerases Ia, Ib, IIa, IIb, and III, respectively, as the normal cells, but the difference was significantly only for IIb.
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PMID:DNA-dependent RNA polymerases of Ehrlich carcinoma, other murine ascites tumors, and murine normal tissues. 117 42

A non-histone protein has been isolated from Ehrlich ascites tumor chromatin. The minimum molecular weight of this non-histone protein, estimated by sodium dodecyl sulfate gel electrophoresis and amino acid analysis, is approximately 10 to 11,000. This non-histone protein is acidic, contains 2.7% alkalilabile phosphorus, binds to DNA, and inhibits transcription of DNA in vitro by the homologous RNA polymerase. The per cent inhibition of RNA synthesis is not affected by increasing amounts of RNA polymerase, but is reduced by addition of excess DNA. In the presence of the non-histone protein, incorporation of [gamma-32P]ATP into RNA in the in vitro RNA synthesizing system is inhibited, with no apparent change in the average chain length of the RNA product. Inhibition of RNA synthesis is completely eliminated if the DNA template is allowed to interact with ATP prior to the addition of the non-histone protein. These results indicate that the observed repression of in vitro RNA synthesis is due to the effect of the non-histone protein on the DNA, inhibiting the initiation of RNA chain formation.
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PMID:Inhibition of transcription in vitro by a non-histone protein isolated from Ehrlich ascites tumor chromatin. 119 69


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