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 synthesis and template properties of T4 vegetative DNA were studied. The DNA-containing material in lysates of cells taken 20 min past T4 infection sediments in sucrose gradients as two major components. Both fractions function as templates for amino acid incorporation in a DNA-dependent in vitro system (coupled transcription-translation). The slower sedimenting activity is not present in uninfected cells and appears in wild type T4-infected cells only after 12 min at 30 degrees, shortly after DNA synthesis starts. It is dependent for its activity on an added S-30 fraction from either uninfected or T4-infected cells and is completely inhibited by deoxyribonuclease or rifampin. On a weight basis the slower sedimenting template is about 30 to 70% as active as mature T4 DNA when supplemented with S-30 extracts from uninfected cells. The spectrum of proteins synthesized in response to the slower sedimenting template is different from that produced in response to mature T4 DNA. In contrast to mature DNA, this template is capable of directing the synthesis of material that precipitates with antiserum directed against whole T4 particles. Thus, it appears capable of directing the synthesis of mRNA for phage structural proteins, i.e. late proteins. The faster sedimenting component is about 8-fold less active for stimulating amino acid incorporation than mature DNA. Significant amounts of RNA polymerase are associated with this DNA in active transcription complexes, yet polyacrylamide gel electrophoresis of the proteins synthesized in response to this fraction show a pattern that resembles the early proteins made from mature T4 DNA in extracts from uninfected cells.
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PMID:Template properties of bacteriophage T4 vegetative DNA. I. Isolation and characterization of two template fractions from gently lysed T4-infected bacteria. 110 12

DNA-dependent RNA polymerase was isolated from rat spleen cell nuclei and was identified as A and B RNA polymerases by data on DEAE- and P-cellulose ionic exchange chromatography and on concentration dependency on bivalent ions and (NH4)2SO4. Two forms of the enzyme differed from each other in the activity in RNA synthesizing system, and their activity was completely inhibited by actinomycin, DNase and RNase.
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PMID:[DNA-dependent RNA polymerase from the nuclei of the spleen of white rats]. 113 3

A special class of non-histone protein ("tight protein") is identified in purified HeLa cell chromatin on the basis of its failure to dissociate from the DNA at very high ionic strength (2.5 M NaCl-5.0 M urea), where over 92% of the total chromatin protein is released. The tight proteins are insoluble in 0.4 N H2SO4 and lack histones as determined by polyacrylamide gel electrophoresis. They have molecular weights between 14,000 and 85,000 with over 70% of the polypeptide chains between 14,000 and 30,000 mol wt. This is the same size range as the non-histone proteins which others have found to display species-specific DNA binding in vitro. There is approximately one molecule of tight protein per 275 DNA base pairs. The tight proteins are characterized by much higher rates of labeling with amino acids than the histones and non-histone chromatin proteins that are dissociated from the DNA by high ionic strength, but they have the lowest phosphorylation levels. Chromatin fractionation experiments were performed to investigate the distribution of tight proteins between template-active and template-inactive regions. Under specific conditions, spleen DNase (DNase II) selectively shears those portions of HeLa cell chromatin that contain nascent RNA transcripts. This nascent RNA-enriched chromatin fraction also contains a high level of the proteins known to be complexed with heterogeneous nuclear RNA in ribonucleoprotein particles and contains over 70% of the RNA polymerase activity of total chromatin. When this method was employed to investigate the distribution of tight proteins, they were found to be almost entirely confined to the template-inactive fraction. Although these experiments do not elucidate the precise function of these proteins, they identify, for the first time, a particular subclass of non-histone chromosomal protein which is distributed asymmetrically between transcriptionally active and inactive chromatin regions.
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PMID:A special class of non-histone protein tightly complexed with template-inactive DNA in chromatin. 114 2

1. The 5'-terminal sequence of the RNA transcribed from bacteriophage fd replicative form DNA under the control of promotor region I has been determined to be ppp(Gp)nUpApApApGpApCpCpUpGpApUpUp. . . 2. This sequence is complementary to the 5'-terminal sequence of the minus strand of the corresponding RNA polymerase binding site I, the starting point for RNA synthesis lying approximately in the middle of the binding site. 3. This initial sequence is also transcribed faithfully from isolated complexes of RNA polymerase and binding site I, obtained by DNase digestion of complexes between RNA polymerase and fd replicative form DNA. These highly stable complexes can not be reconstituted from binding site and enzyme. 4. It is concluded that RNA polymerase binding site and initiation site are identical parts of a promoter region, and that no "drift" between these sites is required as a step in RNA chain initiation. An additional non-transcribed outside region is implicated as essential for full promoter function.
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PMID:Initiation of transcription within an RNA-polymerase binding site. 117

Under specific binding conditions RNA polymerase forms complexes at several sites of the replicative form DNA of bacteriophage fd. One of these complexes becomes stable to both high salt and low temperature after incubation with GTP. None of the complexes is stabilized by ATP. The stabilization by GTP results from the synthesis of an oligo(G) chain, which is bound in the complex. Size and pyrimidine fingerprints of the DNA segment protected by the enzyme against digestion with DNase are not changed upon initiation of oligo(G) synthesis. This result indicates that binding site and initiation site are identical parts of a promoter region.
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PMID:Stabilization of promoter complexes with a single ribonucleoside triphosphate. 117 37

1. Slow, spontaneous lysis of Halobacterium cutirubrum in 3 M-KCl yields DNA-dependent RNA polymerase as a complex with DNA that sediments completely at 45 000g. 2. Controlled deoxyribonuclease digestion of the complex, with or without subsequent sonication, releases the enzyme quantitatively in a soluble form that passes through ultrafilters with a molecular-weight exclusion limit of 50 000. 3. Purification of the active ultrafiltrate by gel filtration and hydroxyapatite chromatography gives a high yield of the purified alpha and beta subunits. 4. The low mol.wt. (17 800-19 000) of the soluble enzyme was confirmed by gel filtration and is unchanged by sonication of the DNA-enzyme complex. 5. A new assay applicable to both forms of the enzyme was developed. 6. The bivalent-cation requirement of the soluble form depends on the buffer concentration. 7. Both the DNA-enzyme complex and the low-molecular-weight soluble forms of the polymerase catalyse formation of short RNA chains only.
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PMID:The relationship between the deoxyribonucleic acid-bound and low-molecular-weight soluble forms of Halobacterium cutirubrum deoxyribonucleic acid-dependent ribonucleic acid polymerase. 120 Sep 99

Ribonucleic acid (RNA)-dependent RNA polymerase activity was demonstrated in the microsomal and ribosomal fraction from the spleen cells of immunized mice. The enzyme activity was solubilized by Triton X-100 from the fraction and partially purified by Biogel A 1.5 m column chromatography. The RNA-dependent RNA polymerase activity was eluted in a single peak from the column. High activity was demonstrated with an RNA polymerase activity was eluted in a single peak from the column. High activity was demonstrated with an RAN preparation (iotaRNA) as template made from the spleens of immunized mice but very low activity was found with an RNA preparation made from the spleens of normal mice. Incorporation of 3H-UTP markedly decreased in the presence of RNase but not in the presence of DNase. DNA preparations made from the spleens of immunized mice were inactive as template for this enzyme. The iotaRNA preparation was fractionated by sucrose density gradient centrifugation. A fraction corresponding to 12-13 S was most active as a template. It was followed by a fraction corresponding to 6-7 S. Sucrose gradient analysis of the 3H-UTP-labeled product was attempted. Some properties of this enzyme are described.
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PMID:Ribonucleic acid-dependent ribonucleic acid polymerase in the immune response. 123 May 9

DNA-dependent RNA polymerase A (or 1) was purified from murine myeloma MOPC 21 by diethylaminoethyl Sephadex chromatography. Further separation from DNA polymerases, protein kinase and DNA endonuclease was accomplished by polyriboadenylate-Sepharose affinity chromatography followed by gradient centrifugation. Yields following chromatography were 100%, but following gradient centrifugation only 25 to 30% of the activity remained. Addition of low-molecular-weight components increased yields to 50 to 60%. Several species of myeloma polymerase A could be detected, and subunits of 190,000 and 125,000 daltons were identified. No evidence of phosphorylation of the polymerase was found.
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PMID:Purification, analysis, and subunits of myeloma (MOPC 21) DNA-dependent RNA polymerase A (1) by polyriboadenylate-sepharose. 125 70

The structure of the elongation complex of vaccinia RNA polymerase halted at discrete template positions was examined by DNase I footprinting. The leading edge of the footprint bore a constant relationship to the catalytic template position, being 22-24 nucleotides (nt) in advance on the nontemplate strand and 17 nt on the template strand. DNase hypersensitivity of the nontemplate strand at the leading edge suggested that the DNA might be distorted as it entered the polymerase molecule. The region of DNA unwinding at the transcription bubble extended at least 12 nt 5' from the catalytic center, as indicated by the reactivity of adenosine residues to diethylpyrocarbonate. Cu-phenanthroline-hypersensitive sites located 13 nt 5' and 4 nt 3' of the growing point appeared to demarcate the margins of the bubble. Strand asymmetry of chemical modification within the bubble was consistent with an RNA-DNA hybrid of no more than 10 base pairs.
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PMID:Structural analysis of ternary complexes of vaccinia RNA polymerase. 143 98

Intact nuclei derived from poorly or highly liver-metastatic murine large-cell lymphoma cell line RAW117 were digested to discrete subchromatin deoxyribonucleoprotein/ribonucleoprotein (DNP/RNP) complexes with Msp-I. The DNP/RNP complexes were composed of DNP/RNPs which were derived from the DNP/RNP complexes by incubation in the presence or absence of DNase-I and subsequent isolation by two-dimensional [isoelectric focusing/sodium dodecylsulfate (SDS)] polyacrylamide gel electrophoresis (PAGE), electroelution from the gel, and removal of SDS. Approximately 450 DNP/RNPs in the two-dimensional gels corresponding to discrete spots or in some cases streaks were analyzed for the presence of v-abl, p53, c-neu, c-H-ras, beta-casein, 18s rDNA, and mu-chain immunoglobulin genes using a hybridization technique. Ten DNP/RNP complexes contained tightly associated p53 DNA, whereas six contained c- or v-abl, four contained mu-chain gene, two contained c-H-ras, one contained dot-blot beta-casein, two contained 18s rDNA, and c-neu was found in one of the DNP/RNPs. The DNP/RNPs were also analyzed for in vitro RNA polymerase and primase activities. To assess the potential transcription abilities of the isolated DNP/RNPs, individual DNP/RNPs or DNP/RNP mixtures (reconstituted after SDS-PAGE separation) were examined for RNA polymerase initiation and synthesis. When RNA products were formed, these were purified by extracellulose chromatography and used as back-hybridization probes for the genes of interest. The RNA products were also analyzed by RNA gel electrophoresis. RNA formation was inhibitable by actinomycin D, and the RNAs formed ranged in size from approximately 80 kbp to approximately 1 kbp. By mixing various DNP/RNP complexes together, different patterns of RNA synthesis were found. For example, one DNP/RNP of M(r) approximately 140,000, isoelectric point (pl) approximately 5.8 synthesized a high molecular weight RNA in vitro that hybridized with beta-casein cDNA, but beta-casein is not expressed in RAW117 cells, suggesting that the silencing of the beta-casein gene was negated by isolation of the DNP/RNP. Mixing this DNP/RNP with two other specific DNP/RNPs again inhibited the synthesis of beta-casein RNA, suggesting that interactions between DNP/RNP complexes can result in differential RNA expression or regulation of RNA polymerases in vitro.
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PMID:Nucleoproteins derived from subnuclear RNA polymerase complexes of metastatic large-cell lymphoma cells possess transcription activities and regulatory properties in vitro. 146 66


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