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)

In an effort to define stage-specific embryonic patterns of sea urchin transcription, we have examined by electron microscopy the distribution of nascent RNP fibrils in dispersed chromatin from nuclei of Strongylocentrotus purpuratus gastrulae. Detailed analysis of individual embryonic nuclei has revealed several new features of nuclear RNA production. Most (82%) of the active chromatin regions observed were represented by only a single fibril. 11% of the active regions contained multiple RNP fibril arrays with an average RNA polymerase density of 1.7 +/- 1.0 polymerases/micron of chromatin and an average contour length of 4.7 +/- 2.8 microns chromatin. An analysis of the lengths of RNP fibrils in single vs. multiple fibril arrays indicates that the differential distribution of RNA polymerases is due to different rates of initiation rather than to different lengths of transcription units (assuming the rate of RNA chain elongation to be constant). We discuss these data in relation to various transcriptional parameters measured by other workers and to EM analyses of other embryonic nuclei. Elucidation of transcriptional patterns in gastrula embryos can provide the basis for further comparative studies of transcription at other stages of sea urchin development in which rates of total genomic transcription vary but the rate at individual loci is as yet unknown.
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PMID:A quantitative electron microscopic analysis of transcription in sea urchin embryos. 44 42

The state of the secondary structure of RNA and proteins comprising nucleoids (cores) and RNP of influenza virus was evaluated comparatively. The identity of RNA conformation in these particles and differences from free RNA conformation due to less marked secondary structure were found. Core proteins were predominantly represented by the beta-framework, and RNP as an alpha-helix. The specific transcriptase activity of the core is significantly lower than RNP activity of influenza virus.
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PMID:[Characteristics of the structural organization and transcriptase activity of the influenza virus nucleoid]. 50 99

We report on the discovery and isolation of DNA- and RNA-containing macromolecular nuclear complexes whose purified major DNA possessed electrophoretic mobilities of approximately 90 and approximately 25 kbp. The deoxyribonucleoprotein-ribonucleoprotein complexes contain RNA and DNA polymerase and primase activities and were isolated from nuclei of murine RAW117 large-cell lymphoma cells by restriction digestion with Msp-I, gentle extraction with solutions containing MgCl2, but without chelating agents, and low ionic strength gel electrophoresis. Two-dimensional (isoelectric focusing/M(r)) gel electrophoresis and silver staining of the proteins of the complexes after treatment with DNase I indicated the presence of approximately 30 protein components. In vitro DNA and RNA polymerase/primase assays showed that the DNP/RNP complexes had very high enzyme specific activities. Using the DNP/RNP complexes a discrete DNA polymerase alpha product of approximately 85 kbp was synthesized that was not synthesized in the presence of the DNA polymerase alpha inhibitor aphidicolin. RNA polymerase assays in the presence of excess alpha-amanitin indicated that the complexes possessed significant RNA polymerase I activity. Preparing the complexes at various times after the release of cells from a double thymidine block showed the complexes as well as the complex-associated enzyme activities to be cell-cycle dependent. The DNA and RNA polymerase-related activities were highest in late S phase, 7 and 9 h, respectively, after release from the double thymidine block. The complexes synthesized a specific in vitro DNA polymerase product using endogenous substrate and nucleotide precursors.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Nucleoprotein complexes released from lymphoma nuclei that contain the abl oncogene and RNA and DNA polymerase and RNA primase activities. 142 73

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

Influenza viruses were disrupted layer by layer with the nonionic detergent NP-40 at fixed pH. Treatment of the virions with NP-40 at neutral or mildly alkaline pH (6.8-8.0) yielded viral core structures containing M1 protein. The matrix M1 protein was selectively extracted from cores at acidic pH 3.0-4.5 with citrate, acetate, and phosphate buffers or with morpholinoethanesulfonic acid. The resulting M1 protein sedimented in a glycerol gradient with a coefficient of 2.8 S and most likely existed as a monomeric form of the 27,000-Da polypeptide. An antigenic map of the monomeric protein M1 tested with a panel of monoclonal anti-M1 antibodies was found to be similar to those of the assembled M1 protein in whole virions. The isolated M1 protein retained biological properties and inhibited the RNA polymerase activity of viral RNP. This transcription-inhibition function of M1 monomers was specifically restricted by one of the monoclonal antibodies studied.
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PMID:Isolation of matrix protein M1 from influenza viruses by acid-dependent extraction with nonionic detergent. 172 9

The nun gene product of the lambdoid coliphage HK022 provokes premature transcription termination at, or near, the phage lambda nut sites. Termination by Nun and antitermination by lambda N protein both require the nut sites and Escherichia coli NusA, NusB and NusE proteins. To characterize further the host requirements for Nun termination, we selected host mutations that blocked termination at lambda nutR. In addition to mutations in nusA, nusB and nusE, we obtained mutations in rpoC, encoding the RNA polymerase beta' subunit. The nusA and rpoC mutations suppressed Nun termination but not antitermination by lambda N function. The mutations antagonized Nun only at lambda nutR; termination at lambda nutL occurred in all the mutant strains. Thus, nutL is not functionally equivalent to nutR. We conclude that the host requirements for Nun termination overlap but are not identical with those for N antitermination, and, in particular, that the beta' subunit of RNP may be Nun-specific.
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PMID:Escherichia coli mutations that block transcription termination by phage HK022 Nun protein. 183 Dec 36

The RNA-dependent RNA polymerase of influenza virus A/PR/8 was isolated from virus particles by stepwise centrifugation in cesium salts. First, RNP (viral RNA-NP-P proteins) complexes were isolated by glycerol gradient centrifugation of detergent-treated viruses and subsequently NP was dissociated from RNP by cesium chloride gradient centrifugation. The P-RNA (P proteins-viral RNA) complexes were further dissociated into P proteins and viral RNA by cesium trifluoroacetate (CsTFA) gradient centrifugation. The nature of P proteins was further analyzed by glycerol gradient centrifugation and immunoblotting using monospecific antibodies against each P protein. The three P proteins, PB1, PB2, and PA, sedimented altogether as fast as the marker protein with the molecular weight of about 250,000 Da. Upon addition of the template vRNA, the RNA-free P protein complex exhibited the activities of capped RNA cleavage and limited RNA synthesis. When a cell line stably expressing cDNAs for three P proteins and NP protein was examined, the three P proteins were found to be co-precipitated by antibodies against the individual P proteins. These results indicate that the influenza virus RNA-dependent RNA polymerase is a heterocomplex composed of one each of the three P proteins and that the RNA-free RNA polymerase can be isolated in an active form from virus particles. Furthermore, the three P proteins form a complex in the absence of vRNA.
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PMID:Purification and molecular structure of RNA polymerase from influenza virus A/PR8. 235 36

One of the most characteristic serologic features of systemic sclerosis (scleroderma) is the occurrence of autoantibodies against nuclear and most notably against nucleolar antigens. This humoral autoimmune response is one of best studied immunologic phenomena in scleroderma. Detailed molecular information on the structure and function, as well as on reactive epitopes of autoantigens targeted by specific serum antibodies, has been revealed by clinical, immunologic, and biochemic studies in several laboratories. Autoantigens such as DNA topoisomerase I (Scl-70), centromere proteins, RNA polymerase I, U3 RNP-associated fibrillarin, PM-Scl, and 7-2 RNP antigens were shown to be specific targets of scleroderma patients and were observed to have clinical correlates within the scleroderma disease spectrum. Therefore, autoantibodies in scleroderma are not only valuable diagnostic tools but also prognosticators of the disease. Although autoantibodies in scleroderma do not appear to play a pathogenetic role in the disease process, the knowledge of the structure and function of their reactive antigens may help in answering questions concerning the etiology of the disease.
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PMID:Autoantibodies against nuclear, nucleolar, and mitochondrial antigens in systemic sclerosis (scleroderma). 240 6

Synthesis of virus-specific RNAs in human HEP-2 and L-41 cells chronically infected with measles virus was studied in comparison with synthesis of viral RNA in acutely infected L-41 cells. The RNA, a component of RNP isolated from chronically infected cells, was shown to be represented mainly by "minus" chains and to contain 23-25% "plus"-RNA. It was demonstrated by blotting hybridization that 1 species of genomic RNA with a molecular weight of 5 megadaltons was synthesized in acute infection whereas in chronically infected cells a small amount of subgenomic RNAs was additionally detected in RNP. The level of virus genome transcription in chronically infected cells was 7-8 fold lower than that in acute infection. The RNA-transcriptase activity of RNP isolated from chronically infected HEP-2 and L-41 cells was also lower than RNP activity from acutely infected L-41 cells. The observed features of virus-specific RNA synthesis in chronically infected cells seem to be likely to play a role in the maintenance of virus persistence.
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PMID:[RNA analysis of the measles virus in a human cell culture of the chronic infection]. 242 50

Immunofluorescence on rat liver sections was used to select high-titer antinucleolar antibodies (ANoA) in the sera of patients with systemic sclerosis (scleroderma). In 646 patients, 53 ANoA sera (8%) were identified, and of these, 46 were available in sufficient quantities for further analysis. The complex of RNA polymerase I was immunoprecipitated by 7 sera (15%), which uniformly produced punctate nucleolar staining. The PM-Scl antigen, a particle consisting of 11 polypeptides, was immunoprecipitated by 8 sera (17%), all of which displayed homogeneous nucleolar staining. A 34-kd nucleolar protein (fibrillarin) of the U3 RNP complex was positive in immunoblotting of 22 sera (48%), which characteristically produced clumpy nucleolar staining. Antibodies against RNA polymerase I were associated with diffuse scleroderma of short duration, which was characterized by a high prevalence of internal organ involvement, including renal crisis. Anti-U3 RNP antibodies had a high prevalence in men with significantly less joint involvement, compared with ANoA-negative patients. Anti-PM-Scl antibodies identified a group of scleroderma patients with a high prevalence of concomitant myositis and renal involvement.
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PMID:Correlates between autoantibodies to nucleolar antigens and clinical features in patients with systemic sclerosis (scleroderma). 245 21


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