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)

Escherichia coli RNA polymerase was assayed with 4 mM Mg2+ and 1 mM Mn2+ using native DNA, heat-denatured DNA, histone-nucleate and isolated rat liver nuclei as the template source. With purified DNA and either or both divalent metal ions, 0.1--5 mM amine stimulated enzyme activity. Spermidine resulted in the greatest stimulation (1.7-fold at 5 mM); whereas, spermine or methylglyoxal bis(guanylhydrazone) first stimulated, then above 3 mM inhibited, the reaction. The addition of unfractionated histone to purified DNA inhibited the reaction by 90%. The subsequent addition of amines resulted in a slight stimulation in incorporation (1.5-fold) in the range of 1--3 mM amine. Alternatively, when enzyme was combined with DNA before histone, only a 20% inhibition was observed and this could be completely prevented by 3 mM spermidine. The addition of amines to isolated nuclei resulted in marked alterations in ultrastructure and Mg2+ content; however, relatively small effects on RNA polymerase activity were observed. With the E. coli enzyme, 0.1--1.0 mM amine stimulated RNA synthesis (1.5-fold) whereas, none of the amines stimulated endogeneous activity in the absence or presence of 300 mM (NH4)2SO4.
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PMID:Effects of polyamines and methylglyoxal bis(guanylhydrazone) on Escherichia coli ribonucleic acid polymerase and the template activity of hepatic cell nuclei in vitro. 62 46

Allopurinol, Collins' solution, and spermidine were tested for their ability to preserve nuclear function during kidney storage. Spermidine increased nuclear ribonucleic acid (RNA) polymerase activity 25 to 43 percent after 60 minutes of warm ischemia. Collins' solution was less effective and allopurinol did not protect RNA polymerase activity. Spermidine offered little additional protection over Collins' during cold storage of RNA polymerase activity. Only spermidine prevented the decrease in the molecular weight of RNA transcribed following kidney storage. Only Collins' solution prevented the breakdown of rapidly labeled heterogenous high molecular weight RNA and ribosomal precursor RNA.
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PMID:Protection of nuclear function by various agents during organ storage. 84 69

Isolated rat liver nuclei demonstrate an increased ability to synthesize RNA in the presence of either spermine or spermidine. Spermidine has more effect on the low-salt alpha-amanitin-insensitive reaction, and spermine has more effect on the high-salt alpha-amanitin-sensitive reaction. Spermine is effective at concentrations of 0.1 mM and 1 muM, showing a biphasic effect. The RNA polymerase activity associated with nuclear chromatin is increased in the presence of spermine only at a concentration of 0.1 mM. Aso the transcription of deproteinized liver DNA by liver form-B polymerase or Escherichia coli enzyme is more efficient in the presence of 0.1 mM-spermine. Only when liver chromatin is transcribed by its homologous enzyme (and not by E. coli enzyme) is spermine active at both 0.1mM and 1 muM as in purified nuclei. The lower concentration of spermine (1 muM) is able to affect chromatin transcription by increasing the affinity of chromatin for the enzyme. Our findings suggest a regulatory role of spermine at the level of genome transcription.
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PMID:The effect of spermine on transcription of mammalian chromatin by mammalian deoxyribonucleic acid-dependent ribonucleic acid polymerase. 109 73

The polyamines of pilose antler (PASPA) consist of putrescine (PU, 70.9%), spermidine (SPD, 26.3%) and spermine (SP, 2.8%). The incorporations of [3H] leucine into protein and [3H] uridine into RNA in mouse liver tissue were increased when PASPA was given orally to mice at the dose of 30 mg/kg for 4 successive days. The incorporations of [3H] leucine into liver protein and [3H] uridine into the cytosolic and nuclear RNA were also increased by treatment with PU (21 mg/kg). In addition, the RNA polymerase activity in the solubilized liver nuclear fraction of PU (21 mg/kg)-treated mice was increased. SPD only promoted the synthesis of protein in mouse liver tissue at the dose of 8 mg/kg. However, SP showed no effect on the synthesis of protein and RNA polymerase activity under the used dose (1 mg/kg). The results suggest that PASPA is the main active substance responsible for the promotion of the synthesis of protein and RNA in mouse liver.
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PMID:[Influence of the active compounds isolated from pilose antler on syntheses of protein and RNA in mouse liver]. 170 79

All three polyamines - putrescine, spermidine and spermine stimulated the activity of mycobacterial RNA polymerase in vitro although the concentration required for maximal stimulation was different for each of the amines. Spermidine and spermine showed a biphasic effect on the enzyme activity. Stimulation of RNA synthesis by spermidine occurs only at higher DNA template/enzyme ratio. Spermidine stimulates RNA synthesis by acting on the elongation phase of RNA synthesis but it had no effect on initiation phase. Addition of mycobacterial RNA to the assay mixture resulted in the inhibition of RNA polymerase activity and this inhibition could be reversed by spermidine suggesting that spermidine stimulates transcription by binding to nascent RNA and thus destabilizing the short DNA-RNA hybrid region.
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PMID:Role of polyamines in the synthesis of RNA in mycobacteria. 245 96

Little is known about the cellular mechanisms responsible for the trophic effects of cholecystokinin (CCK) and secretin on the rat pancreas, and controversy exists with regard to the interaction between these two peptides. In the present study attempts were made to elucidate the time course of events leading to pancreatic growth and to clarify the interaction between the peptides when given as continuous, long-term intravenous infusions to rats. A cholecystokinin-like peptide (CCK-LP) and secretin were given as a continuous intravenous infusion to conscious and unrestrained animals with free access to food and water for 0.5, 1, 2, 4, 6, 8, 12, 24, 48, and 96 h. The pancreas was quickly removed and analyzed for variables indicating synthesis and accumulation of DNA, RNA, and polyamines. CCK-LP increased the activity of RNA polymerase already after 1 h, whereas an increase in the activity of ornithine decarboxylase (ODC) and the level of putrescine was seen at 4 h. Spermidine was increased after 12 h. The activities of DNA polymerase and thymidine kinase were increased at 12 and 24 h, respectively, whereas the total contents of DNA and RNA were first increased at 48 h. Secretin alone showed a marked but short-lived effect on polyamine synthesis and a weak effect on the variables indicating protein synthesis and growth. When the two peptides were given together, a large but transient potentiation of ODC activity was observed, whereas no interaction was seen on polyamines, RNA synthesis, or pancreatic growth. The present study confirms the trophic effects of CCK and secretin on the rat pancreas but fails to confirm an interaction between the two peptides on growth. Both peptides stimulate polyamine synthesis, and ODC appears to be an early and sensitive indication of their trophic effect. The initiation of RNA synthesis appears to be independent of the ODC activity.
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PMID:Short- and long-term effects of secretin and a cholecystokinin-like peptide on pancreatic growth and synthesis of RNA and polyamines. 247 84

The effect of polyamines on T7- and lambda rifd18 DNA-directed synthesis of proteins in an Escherichia coli cell-free system has been studied. When T7 DNA was used as a template, the degree of stimulation by spermidine of protein synthesis was larger with T7 RNA polymerase than with Mr 42 K protein, while the synthesis of Mr 13.5 K protein was not stimulated significantly by spermidine. The synthesis of T7 RNA polymerase was stimulated approx. 10-fold by 1 mM spermidine. When lambda rifd18 DNA was used as a template, the synthesis of beta beta' subunits of RNA polymerase was stimulated greatly by spermidine, while the synthesis of elongation factor Tu and ribosomal proteins was not stimulated significantly by spermidine. Spermidine stimulation of T7 DNA-directed synthesis of T7 RNA polymerase was at the level of both translation and transcription. The degree of stimulation by spermidine was greater at the level of translation. Putrescine stimulated the synthesis of T7 RNA polymerase and Mr 42 K protein to a small degree at the level of translation.
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PMID:Differential stimulation by polyamines of phage DNA-directed in vitro synthesis of proteins. 622 14

Electron microscopy and the biological properties of susceptibility to DNase I, genetic transcription, and transformation of pBR322 DNA compacted with spermidine or hexammine cobalt (III), were analyzed in order to characterize the association of DNA in its compacted form with these two different trivalent cations. Spermidine and hexammine cobalt (III) produced an average 4-fold reduction of the DNA perimeter in compact DNA forms, which were doughnut-shaped toroids and cylinders. Both compacted DNAs were resistant to the hydrolytic activity of DNase I. However, spermidine-condensed pBR322 DNA was 10-fold and 4 to 6-fold more active in transcription and transformation, respectively, than naked pBR322. I. Hexammine cobalt (III)-condensed pBR322 was inactive in both biological properties. An inhibitory effect of hexammine cobalt (III) on RNA polymerase and genetic transformation activities was discarded because at higher ionic strength, in which DNA is not compacted by hexammine cobalt (III), transcription and transformation were similar to those observed with naked DNA. This information showed that the interaction of hexammine cobalt (III) with the DNA converted the pBR322 DNA into an inert molecule. In contrast, pBR322 did not loose its biological properties after its interaction with the polyamine spermidine; i.e., experimental condensation of pBR322 DNA by spermidine produced compacted DNA that is more similar to compact native genomes than relaxed DNA. These experiments led us to conclude that spermidine-condensed DNA can be used to study the roll of the native supercoiling of DNA in the regulation of genetic replication and transcription, as well as to study the mechanisms that allow the accessibility of the supercoiled or condensed DNA substrate for enzymes.
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PMID:Electron microscopy and biological properties of pBR322 DNA condensed with the trivalent cations spermidine and hexammine cobalt (III). 1093 14

The mammalian reovirus (MRV) genome comprises 10 double-stranded RNA (dsRNA) segments, packaged along with transcriptase complexes inside each core particle. Effects of four small molecules on transcription by MRV cores were studied for this report, chosen for their known capacities to alter RNA duplex stability. Spermidine and spermine, which enhance duplex stability, inhibited transcription, whereas dimethyl sulfoxide and trimethylglycine, which attenuate duplex stability, stimulated transcription. Different mechanisms were identified for inhibition or activation by these molecules. With spermidine, one round of transcription occurred normally, but subsequent rounds were inhibited. Thus, inhibition occurred at the transition between the end of elongation in one round and initiation in the next round of transcription. Dimethyl sulfoxide or trimethylglycine, on the other hand, had no effect on transcription by a constitutively active fraction of cores in each preparation but activated transcription in another fraction that was otherwise silent for the production of elongated transcripts. Activation of this other fraction occurred at the transition between transcript initiation and elongation, i.e., at promoter escape. These results suggest that the relative stability of RNA duplexes is most important for certain steps in the particle-associated transcription cycles of dsRNA viruses and that small molecules are useful tools for probing these and probably other steps.
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PMID:Probing the transcription mechanisms of reovirus cores with molecules that alter RNA duplex stability. 1929 68