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 influence of cortisol and prolactin on casein gene expression in the mammary gland of lactating BALB/c mice was measured by using a specific cDNA probe to 15S casein mRNA (cDNAcsn). Casein mRNA (mRNAcsn) level in the mammary gland was decreased by 85% 5 days after adrenal ablation, but then was increased 4.4-fold 12 hr after a single injection of hydrocortisone-21-acetate. An 80% decrease in serum prolactin level, induced by the prolactin inhibitor 2-bromo-alpha-ergocryptin (CB-154), did not alter the level of mRNAcsn in the gland. Specific transcription of the casein gene in nuclei isolated from lactating mammary glands was measured by cDNAcsn hybridization to the in vitro synthesized Hg-CTP-containing RNA (Hg-RNA), which was purified by SH-agarose chromatography. The level of the mRNAcsn in Hg-RNA synthesized in the isolated nuclei was 0.09% and this was decreased 85% by alpha-amanitin, indicating that the mRNAcsn sequences in the Hg-RNA were the products of RNA polymerase II-directed DNA-dependent RNA synthesis. Transcription of the mRNAcsn in isolated nuclei was decreased by 70% 5 days after adrenalectomy and a single injection of the glucocorticoid then increased the transcription level 2-fold at 6 hr. Essentially no alteration of the level of transcription was detectable in mammary nuclei isolated from lactating mice with 80% decreased serum prolactin level, induced by CB-154 treatment. The results thus demonstrate a glucocorticoid involvement on the modulation of casein gene expression at the transcriptional level of control.
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PMID:Glucocorticoid modulation of casein gene transcription in mouse mammary gland. 29 34

In searching for regulatory mechanisms involved in the cell-specific neuronal and glial transcription a cell-free transcriptional system has been developed using neuronal and glial rat brain chromatin and partially purified neuronal and glial nuclear rat brain RNA polymerases. Both free and chromatin-bound (engaged) neuronal and glial RNA polymerase fractions were separated from isolated neuronal and glial rat brain nuclei to determine their transcriptive efficiency. A double number of RNA initiation sites was measured on the neuronal when compared to the glial chromatin, independently of whether the neuronal or the glial RNA polymerase preparation was used for the determination. Structural modification of the neuronal and glial chromatin template by acetylation with acetyl-coenzyme A leads to an increase of the total number of RNA initiation sites available for exogenously added rat brain RNA polymerase. This indicates that acetylation of chromatin-bound proteins is capable to render primarily restricted gene sequences transcriptable. A positive correlation exists between the extent of acetate uptake by neuronal and glial chromatin-bound histone fractions and the extent of the increase of the number of RNA initiation sites is specifically related to histone acetylation rather than to acetylation of any other chromatin protein. Significant information in this respect could be achieved by dissociation of chromatin into its principal components and selectively reconstituting DNA with specifically acetylated histone and non-histone proteins.
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PMID:Studies on the regulation of RNA synthesis in neuronal and glial nuclei isolated from rat brain. 64

Reovirus infectivity and core-associated RNA polymerase activity were decreased by irradiation with long wavelength ultraviolet light in the presence of the 4'-substituted psoralen derivatives, 4'-aminomethyl-4,5',8-trimethylpsoralen and 4'-hydroxymethyl-4,5',8-trimethylpsoralen. Monoadduct formation occurred after photoreaction with low psoralen concentrations or brief irradiation times, and the presence of KCl or magnesium acetate had a protective effect. Under the mild reaction conditions in which 1 molecule of 4'-aminomethyl-4,5',8-trimethylpsoralen was bound covalently per 160 to 290 base-pairs, the polymerase activity was decreased by greater than 90%. At higher drug concentrations or longer times of photoreaction of reovirus cores, the viral RNA was extensively cross-linked indicating that the reovirus genome in situ is double-stranded.
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PMID:Photochemical cross-linking of reovirus genome RNA in situ and inactivation of viral transcriptase. 72 5

RNA polymerase was isolated from Escherichia coli and Serratia marcescens. The subunits of both enzymes were separated by electrophoresis on cellulose acetate sheets in the presence of urea. Under conditions favouring reconstitution of the RNA polymerases, stoichiometric amounts of the subunits were allowed to interact. Active hybrid enzymes were formed if corresponding subunits of both enzymes were mutually exchanged. The analysis of the RNA products synthesized showed that the reconstituted enzymes are able to recognize the promoters for transcription and the termination signals on the DNA template. The transcription products can serve as messengers for cell-free protein synthesis.
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PMID:Functional hybrid enzymes reconstituted from Escherichia coli and Serratia marcescens RNA polymerase subunits. 77 Jan 71

5-Formyl-1-(alpha-D-ribofuranosyl)uracil 5'=triphosphate has been used to affinity label E. coli DNA-dependent RNA polymerase. It is a noncompetitive inhibitor of the enzyme with Ki=0.54 mM. A short preincubation of the enzyme and alpha-fo5UTP is required to achieve maximum inhibition, and the entent of the inhibition is dependent upon the alpha-fo5UTP concentration. When a preincubation mixture of alpha-fo5UTP/enzyme is diluted, the enzyme regains activity with time showing that the inhibition is reversible, presumably occurring by Schiff base formation between an amino group on the enzyme and the formyl group. Upon sodium borohydride reduction of an enzyme/alpha-fo5UTP preincubation mixture the enzyme is irreversibly inhibited. alpha-fo5UTP is more effective in inhibiting the enzyme than alpha-fo5U, and the inhibition is decreased by the presence of ATP, UTP, or GTP in the preincubation mixture, suggesting that inhibition is occurring at a triphosphate binding site. The stoichiometry of binding of alpha-fo5UTP to the enzyme was determined using the gamma-32P-labeled derivative. After a 20-s preincubation of enzyme/alpha-fo5UTP followed by NaBH4 reduction the stoichiometry of binding was 1.1:1 (alpha-fo5UTP bound: inactivated enzyme), and this rose to 2.42:1 after a 10-min preincubation. After a 20-s preincubation the [gamma-32P]-alpha-fo5UTP was shown to be located on the beta subunit of RNA polymerase by cellulose acetate electrophoresis in 6 M urea.
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PMID:Affinity labeling of Escherichia coli DNA-dependent RNA polymerase with 5-formyl-l-(alpha-D-ribofuranosyl)uracil 5'-triphosphate. 77 15

Studies were undertaken to understand the control of synthesis, stability and modification of UDP galactose epimerase and DNA-dependent RNA polymerase during sporulation of Saccharomyces cerevisiae. When a pre-induced culture of an inducible strain (wild type) is transferred to sporulation medium, the epimerase is inactivated to an undetectable level within 16 hours. Surprisingly, the addition of cycloheximide, a protein synthesis inhibitor, during sporulation stabilizes the epimerase activity. However, in a constitutive strain, the epimerase continues to be synthesized de novo during sporulation. Since the enzyme is synthesized during both vegatative growth and sporulation constitutively, the controls for synthesis of epimerase must be similar under these physiologically different conditions. After chromatography on DEAE Sephadex, there is no change observed in the elution patterns of RNA polymerase forms extracted from acetate growth vegetative cells, sporulating cells or from mature asci ; in all cases RNA polymerase consists of three forms, Ib, II and III. However, single spore suspension obtained from asci by treatment with zymolase contains a new form with chromatographic properties similar to those of form Ia. Our data suggests that form Ia may be a modification product of from Ib.
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PMID:Control of enzyme synthesis and stability during sporulation in Saccharomyces cerevisiae. 78 57

The intravenous injection of the lighter lanthanide ions Pr(III), Nd(III), and Sm(III) in doses of 35 mumoles/kg inhibits, and isoosmolar doses of the heavier lanthanide ions Gd(III), Dy(III), and Er(III) stimulate rat liver nuclear in vitro RNA synthesis catalyzed by RNA polymerase B 24 h after their application, while nuclear RNA synthesis, catalyzed by RNA polymerase A, was inhibited by the same isoosmolar doses of Pr(III), Nd(III) and not influenced by Sm(III), Gd(III), Dy(III), or Er(III). The effect of in vivo applied Pr(III) and Nd(III) on rat liver in vitro nuclear RNA synthesis shows a similar time and dose-dependent pattern. The decreased rat liver nuclear in vitro RNA synthesis 24 h after intravenous injection of Pr(III) as well as after Nd(III) was accompanied by a decreased nuclear in vitro 3H-acetate uptake by the chromatin-bound histone fractions, F 2a2, F 3, and F 2al. At the same time after the Pr(III) injection, the capacity and number of initiation sites of the rat liver nuclear template for homologous nuclear RNA polymerases, prepared from control rat liver nuclei, was lower than the corresponding control template. A decreased activity of endogenous free nuclear RNA polymerases, as determined with the aim of the synthetic poly(dA-dT) template 24 h after Pr(III), may further contribute to the decreased nuclear RNA synthesis. The results indicate a primary ionic size-correlated interference of lanthanides with the nuclear control mechanisms of RNA synthesis.
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PMID:On the mechanism of lanthanide-induced liver toxicity. 98 11

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

In vitro infectivity of the MT4 lymphoid cell line with human immunodeficiency virus (HIV) has been studied in correlation with the degree of expression of the CD4 molecule at the cell surface. To modulate this CD4 expression in vitro, pre-incubation with phorbol myristate acetate (PMA) was used. The lowest CD4 expression was obtained after 1 to 5 hours. Thereafter, a partial re-expression of OKT4 was observed, e.g., when the incubation time with PMA was extended to 20 hours. Reverse transcriptase (RT) activity decreased and was delayed proportionally to the length of incubation of cells with PMA. This observation was confirmed by the comparable variation of cytopathic effects and of p24 antigen release in culture supernatants. The decrease in HIV infectivity hence correlated with that of OKT4 expression when PMA treatment did not exceed a few hours. By contrast, after extended treatment, infectivity remained decreased although OKT4 expression reappeared.
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PMID:Phorbol ester induces down-regulation of CD4 molecule expression and resistance to in vitro infection by HIV1. 128 70

After exposure of bovine pulmonary artery endothelial cells in culture to 1 microM dexamethasone for 24-48 h, angiotensin-converting enzyme (ACE) activity of these cells was elevated severalfold. The increase in ACE activity was preceded by an increase in ACE mRNA, which could be detected after treatment of cells with dexamethasone for 4 h. When the increase in ACE mRNA produced by dexamethasone at 4 h was blocked by alpha-amanitin, an RNA polymerase II inhibitor, the increase in ACE activity detected at 48 h was inhibited. RU 38486, a steroid receptor antagonist, inhibited the elevation of both ACE activity and mRNA produced by dexamethasone. Among other steroids tested, only hydrocortisone, aldosterone and corticosterone-21-acetate had a stimulatory effect on ACE activity. RU 38486 effectively blocked the elevation in ACE activity produced by both aldosterone and dexamethasone, but had no effect on the elevation of ACE activity produced by other agents (3-isobutyl-1-methylxanthine, A23187, and dibutyryl adenosine 3',5' cyclic monophosphate). From these data we conclude that dexamethasone and certain other steroids with an hydroxyl group in the 11th carbon position regulate ACE gene expression of bovine endothelial cells at the transcriptional level via a steroid receptor-mediated mechanism.
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PMID:Stimulation of bovine pulmonary artery endothelial cell ACE by dexamethasone: involvement of steroid receptors. 133 98


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