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:3.1.27.4 (ribonuclease)
6,621 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

At 1--3 hours after infection of chick fibroblasts and a continuous dog kidney cell line MDCK with WSN and FPV viruses large virus specific structures were found containing parent nucleocapsids, newly synthesized virus-specific RNA and newly synthesized protein. The buoyant density of these structures in cesium chloride was 1.30--1.32 g/ml. The amount of newly synthesized RNA and protein in these structures increased linearly for 3 hours of infection. The parent and newly synthesized RNA in the structures were resistant to ribonuclease. When protein synthesis was inhibited by cycloheximide, parent nucleocapsids were also found in the large structures, and primary transcription of the viral genome occurred there as well. Some structures were destroyed upon sonication of the nuclei. It is suggested that in the observed structure the parent nucleocapsids are associated with cell components (possibly, nuclear chromatin), and centers of influenza virus reproduction arise in the sites of association.
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PMID:[Intranuclear centers of influenza virus reproduction during the early stage of infection]. 56 91

Two procedures for characterising the genomes of recombinant influenza viruses are described. The first of these involves ribonuclease T4 oligonucleotide fingerpart analysis of separated viral RNAs labelled either in vivo or in vitro and the second utilises polyacrylamide gel electrophoresis to identify the double-stranded molecules formed by hybridisation between the complementary and virion RNAs of two viruses. Although the latter method is more suitable for routine screening purposes, both procedures are suitable for distinguishing between equivalent RNA components of closely related viruses.
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PMID:Procedures for characterisation of the genetic material of candidate vaccine strains. 60 97

Purified influenza virus contains ribonuclease activity. The enzyme does not hydrolyze viral RNA but both 28 S and 18 S host cell RNA are degraded forming large (about 16 S) and small (about 5 S) fragments with the release of the acid-soluble material. It has an optimum temperature of 37 degrees C, requires no divalent ions, and is inhibited by 0.1 M EDTA and 1% SDS. Treatment with 4 M urea increases enzymatic activity considerably (42%) but is not a prerequisite for eliciting ribonuclease activity suggesting that the enzyme is probably located near the surface of the virus particle. Results show that the observed enzyme activity is virus-associated as no host cell protein is detectable in the purified virus.
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PMID:Association of a ribonuclease with the purified influenza virus. 81 84

The antiviral activity of a bacterial ribonuclease conjugate with chitosane of Kamchatka crab (in a form of water soluble chito-oligosaccharides) has been studied. The conjugate inhibitory activity for A and B viruses as well as to Sindbis arbovirus in tissue cultures is shown. The preparation efficiency at intramuscular and intranasal administration was observed at experimental influenza infection of white mice.
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PMID:[The antiviral action of a modified bacterial ribonuclease]. 130 13

Nuclei purified from chicken embryo fibroblast cells infected with influenza (fowl plague) virus contain an RNA-dependent RNA polymerase. The in vitro activity of this enzyme is insensitive to actinomycin D, and is completely destroyed by preincubation with ribonuclease. Enzyme induction is prevented if cells are treated with actinomycin D or cycloheximide at the time of infection. RNA-dependent RNA polymerase activity increases rapidly in cell nuclei from 1 h postinfection, reaches a maximum at 3 to 4 h, then declines; a similar RNA polymerase activity in the microsomal cell fraction increases from 2 h postinfection and reaches a maximum at 5 to 6 h. The characteristics of the nuclear and microsomal enzymes in vitro are similar with respect to pH and divalent cation requirements. The in vitro products of enzyme activity present in the nuclear and microsomal fractions of cells infected for 3 and 5 h were characterized by sucrose density gradient analysis, and annealing to virion RNA. The microsomal RNA polymerase product contained 67 and 93% RNA complementary to virion RNA at 3 and 5 h, respectively; for the nuclear RNA polymerase product these values were 40% in each case.
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PMID:RNA-dependent RNA polymerase in nuclei of cells infected with influenza virus. 435 67

The properties of the ribonucleic acid (RNA) synthesized by the influenza (WSN) virion polymerase have been investigated. Most of the product RNA is synthesized in association with virion RNA species from which it can be released by heat treatment as single-stranded, ribonuclease-sensitive polynucleotides (average molecular weight, 2-hr sample, about 10(5) daltons). At least 95% of the product is complementary to the viral RNA species. On the basis of the molar ratio of the RNA species isolated from a (3)H-uridine-labeled virus preparation, it was calculated that the WSN genome consists of seven pieces of RNA with a sum molecular weight of about 5 x 10(6) daltons.
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PMID:Transcription of the influenza ribonucleic acid genome by a virion polymerase. II. Nature of the in vitro polymerase product. 510 47

A ribonuclease-resistant ribonucleic acid (RNA) with a sedimentation coefficient of 12S was obtained by self-annealing influenza virus-specific RNA isolated from infected cells. It had the properties of double-stranded RNA. (i) Sedimentation behavior in sucrose gradient was independent of salt concentration. (ii) Thermal transition profile was sharp; the melting temperature is 83 C in 0.1 SSC (0.15 m NaCl plus 0.015 m sodium citrate) and 98 C in SSC. (iii) Buoyant density in cesium sulfate was 1.58 g/cm(3) compared to 1.64 g/cm(3) for single-stranded RNA. (iv) It gave rise to single-stranded RNA after denaturation. (v) The 12S RNA duplex contained both plus and minus strands of influenza virus. Labeled plus strands could be displaced by extraneous cold plus strands and extraneous (32)P-labeled plus strands could be incorporated into duplex after denaturation and reannealing.
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PMID:Characterization of influenza virus ribonucleic acid duplex produced by annealing in vitro. 581 52

Two enzymatic activities hydrolysing ribonucleoside 2', 3'-cyclic phosphates (2', 3'-cNMP) to 2'- or 3'- nucleoside monophosphate were found associated with influenza and Newcastle disease viruses. The two enzymatic activities differed from each other by temperature optima and thermoresistance. 2', 3'-Cyclic nucleotide 3'-phosphohydrolase was responsible for splitting of the substrate to 2'-NMP. Splitting of the substrate to 3'-NMP was due either to ribonuclease or to 2', 3'-cyclic nucleotide 2'-phosphohydrolase.
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PMID:Hydrolysis of ribonucleoside 2',3'-cyclic phosphates by influenza and Newcastle disease viruses. 611 52

The addition of detergent-solubilized influenza C virus to a reaction mixture containing ATP, CTP, GTP, [3H]UTP, and Mg2+ leads to the synthesis of an acid-insoluble, radioactive product, which is ribonuclease-sensitive. The dinucleoside monophosphate ApG clearly enhances the reaction rate, a fact which indicates that influenza C viruses follow the same strategy of transcription as influenza A and B viruses, the other members of the orthomyxovirus family.
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PMID:Influenza-C-virion-associated RNA-dependent RNA-polymerase activity. 654 51

Ribonucleoprotein (RNP) cores with RNA-synthesizing activity were prepared in two fractions, M protein-free and M protein-associated, from detergent-treated influenza virus PR8 by centrifugation through a discontinuous triple gradient of cesium sulfate, glycerol, and NP-40. The M-free RNP was fractionated by phosphocellulose column chromatography into two major RNP forms, A and B, which differed in the content of P proteins, while the M-associated RNP gave only the low P-content Form-B RNP. Starting from the high P-content Form-A RNP, an RNA-P proteins complex virtually free from NP protein was isolated by cesium sulfate equilibrium centrifugation. The complex, containing only three P proteins (P1, P2, and P3), was still active in catalyzing RNA synthesis in vitro without addition of exogenous template, indicating that NP protein is not required for the catalysis of RNA synthesis. RNA synthesis by the isolated RNA-P proteins complex was dependent on either ApG or capped RNA primers, and required four ribonucleoside triphosphates as substrates. The RNA product in this reaction was hybridizable to viral RNA. A complex of one each of the three P proteins was separated from RNA by glycerol gradient centrifugation after ribonuclease treatment or cesium chloride equilibrium centrifugation.
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PMID:RNA polymerase of influenza virus. III. Isolation of RNA polymerase-RNA complexes from influenza virus PR8. 686 42


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