Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.27.1 (RNase)
 16,360 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Addition of the human placental RNase inhibitor at 10 mu/ml to a mixture of wheat germ extract and translation components, prior to the addition of mRNA from dog pancreas or influenza virus-infected cells, resulted in a significant increase in the yield of proteins synthesized. Analysis of the translation products by sodium dodecyl sulfate/polyacrylamide gel electrophoresis indicated that the inhibitor preferentially increased the yield of the larger proteins. In the presence of the inhibitor, yields of the preprocarboxypeptidases were increased 4.5-fold and yields of preamylase were increased 15-fold. Incubation of the wheat germ extract or individual translation components with dog pancreas mRNA, with or without the placental inhibitor, indicated significant RNase contamination among the fractions. Two other in vitro protein synthesis systems-the reticulocyte lysate system and the Krebs ascites system-were found to contain latent RNase activity (RNase in complex with the inhibitor) and an excess of RNase inhibitor. The addition of placental RNase inhibitor did not increase the yield in these systems, except in those cases in which the RNase contamination approached the amount of endogenous inhibitor. When used during the isolation of rat liver cell fractions, the placental inhibitor increased the yield (as measured by A(260)) of rough microsomes and detached polysomes by 24% and 4.6-fold, respectively. Analysis of translation products indicated that detached polysomes isolated in the presence of the inhibitor were intact; those isolated in the absence of inhibitor were degraded.
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PMID:Role of mammalian RNase inhibitor in cell-free protein synthesis. 29 94

A clone of recombinant virus obtained from the cross between WSN and Hong Kong strains of influenza virus gave rise to progeny containing predominantly von Magnus particles. In the electropherogram of virus RNA, the P3 gene was markedly diminished, and a new species of RNA (extra RNA) was present in addition to eight gene segments. The origin of the extra RNA was studied by two-dimensional gel electrophoresis of T1 RNase-generated oligonucleotides. Four out of five large oligonucleotide spots present in the extra RNA matched to those contained by the P3 gene. It was concluded that the extra RNA was derived from the P3 gene probably by deletion. The possible origin of the spot which was present in the extra RNA but not in eight gene segments including P3 was discussed.
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PMID:Origin of small RNA in von Magnus particles of influenza virus. 44 97

In freeze-thaw lysates of MDCK cells infected with 32P-labeled influenza virus A/WSN in the presence of added RNase, acid-precipitable radioactivity diminished to about 50% of initial values within 90 min after a 1-h virus adsorption period. A similar preparation containing rimantadine at a concentration of 50 micrograms/ml exhibited only a 10% reduction in acid-precipitable radioactivity. These findings suggest that rimantadine interferes with uncoating of influenza virus in infected cells.
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PMID:Inhibition of influenza virus uncoating by rimantadine hydrochloride. 50 98

Ribonucleoproteins (RNPs) isolated from infectious and defective interfering (DI) influenza virus (WSN) contained three major RNP peaks when analyzed in a glycerol gradient. Peak I RNP was predominant in infectious virus but was greatly reduced in DI virus preparations. Conversely, peak III RNP was elevated in DI virus, suggesting a large increase in DI RNA in this fraction. Labeled [(32)P]RNA was isolated from each RNP region and analyzed by electrophoresis on polyacrylamide gels. Peak I RNP contained primarily the polymerase and some HA genes, peak II contained some HA gene but mostly the NP and NA genes, and peak III contained the M and NS genes. In addition, peak III RNP from DI virus also contained the characteristic DI RNA segments. Interference activity of RNP fractions isolated from infectious and DI virus was tested using infectious center reduction assay. RNP peaks (I, II, and III) from infectious virus did not show any interference activity, whereas the peak III DI RNP caused a reduction in the number of infectious centers as compared to controls. Similar interference was not demonstrable with peak I RNP of DI virus nor with any RNP fractions from infectious virus alone. The interference activity of RNP fractions was RNase sensitive, suggesting that the DI RNA contained in DI RNPs was the interfering agent, and dilution experiments supported the conclusion that a single DI RNP could cause interference. The interfering RNPs were heterogeneous, and the majority migrated slower than viral RNPs containing M and NS genes. These results suggest that DI RNP (or DI RNA) is also responsible for interference in segmented, negative-stranded viruses.
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PMID:Defective influenza viral ribonucleoproteins cause interference. 50 5

Reovirus mRNA's containing a 5'-terminal methylated cap structure (m(7)GpppG(m)) were shown to be effective primers for influenza viral RNA transcription in vitro catalyzed by the influenza virion transcriptase. Priming activity required the presence of methyl groups in the cap since reovirus mRNA's with 5'-terminal GpppG were inactive as primers. Both the cap and internal nucleotides were physically transferred from radiolabeled reovirus mRNA to influenza viral complementary RNA (cRNA) during transcription in vitro. By using reovirus mRNA's with methyl-(3)H-labeled caps as primers, we showed that the influenza viral cRNA synthesized in the presence of unlabeled nucleoside triphosphates contained [methyl-(3)H]m(7)GpppG(m), identical to that found in the reovirus mRNA primer. To demonstrate transfer of internal residues, reovirus mRNA's synthesized in the presence of all four alpha-(32)P-labeled ribonucleoside triphosphates were used as primers. The resulting influenza viral cRNA was (32)P-labeled. Diethyl-aminoethyl-Sephadex chromatography of the RNase T2 digest of this cRNA demonstrated (32)P radiolabel in both internal residues (charge -2) and the cap (charge -4.6). Approximately 25 internal nucleotides along with the cap of reovirus mRNA were transferred to each chain of influenza viral cRNA. Gel electrophoretic analysis indicated that the segments of influenza viral cRNA primed by reovirus mRNA were approximately the same size as those primed by a different mRNA, globin mRNA, strongly suggesting that the influenza virion transcriptase complex transfers approximately the same number of nucleotides plus the cap from different mRNA primers to the 5' end of influenza viral RNA transcripts.
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PMID:Cap and internal nucleotides of reovirus mRNA primers are incorporated into influenza viral complementary RNA during transcription in vitro. 51 5

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

In the presence of Mg(2+) and a specific primer, ApG or GpG, the influenza WSN virion transcriptase synthesizes large, polyadenylic acid-containing complementary RNA (cRNA) (Plotch and Krug, J. Virol., 21:24-34, 1977). After removal of its polyadenylic acid with RNase H in the presence of polydeoxythymidylic acid, the in vitro cRNA distributed into seven discrete bands during electrophoresis in acrylamide gels containing 6 M urea. The eight known segments of virion RNA (vRNA) also distributed into seven bands under these conditions as two, rather than the expected three, large-sized segments were resolved. Each of the in vitro cRNA segments migrated slightly faster than the corresponding vRNA segment. To determine whether this difference in mobility reflects a difference in size between cRNA and vRNA, the double-stranded RNA formed by annealing labeled in vitro cRNA to unlabeled vRNA was subjected to various nuclease treatments and was analyzed by gel electrophoresis. Hybrids treated with RNase T2 or a combination of RNase T2 and RNase H migrated slightly faster than those treated only with RNase H, indicating that RNase T2 removed an RNA sequence other than polyadenylic acid, most probably a short sequence of vRNA not hydrogen bonded to cRNA. These results suggest that the in vitro cRNA segments are shorter than, and thus incomplete transcripts of the corresponding vRNA segments. All eight hybrids were resolved by gel electrophoresis, indicating that all eight vRNA segments are transcribed into cRNA in vitro. We also present evidence suggesting that the ApG primer initiates in vitro transcription exactly at the 3' end of vRNA.
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PMID:Segments of influenza virus complementary RNA synthesized in vitro. 62 84

Influenza A viruses induce the accumulation of electron-dense inclusions in the cytoplasm of infected cells during the latter stages of the replication cycle. Cell fractionation studies showed that these inclusions could be recovered in subcellular fractions containing ribosomes and polysomes. Isolation of these inclusions was accomplished by procedures involving RNase treatment of these fractions followed by repurification, or by fluorocarbon extraction and gradient centrifugation. Electron microscopy indicated that the isolated inclusions exhibited a major periodicity of approximately 8 nm with minor periodicities of approximately 4 nm. Analysis by sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed that the influenza virus coded nonstructural protein was the only protein component present in isolated inclusions.
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PMID:Isolation and characterization of cytoplasmic inclusions from influenza A virus-infected cells. 62 86

In the presence of Mg(2+) and a specific dinucleotide primer (ApG or GpG), the influenza virion transcriptase synthesizes the eight discrete segments of complementary RNA (cRNA) containing polyadenylic acid (Plotch and Krug, J. Virol. 21:24-34, 1977). Virions were examined for their ability to cap and methylate cRNA containing di- or triphosphorylated 5' termini. By using the primers ppApG, pppApG, or ppGpG, viral cRNA was synthesized in vitro with [alpha-(32)P]-GTP and S-[methyl-(3)H]adenosylmethionine as labeled precursors. DEAE-Sephadex chromatography of the RNase T2 digest of the cRNA product demonstrated no (3)H incorporation at all and the absence of a (32)P-labeled cap structure. The 5' terminus of ppApG-primed cRNA could be capped and methylated by enzymes from vaccinia virus, indicating that the two 5'-terminal phosphates derived from the primer were preserved in the product cRNA. The cap structure formed by the vaccinia enzymes and released by RNase T2 digestion as m(7)GpppA(m)pGp was radioactively labeled at its 3'-terminal phosphate only when [alpha-(32)P]CTP was used as the labeled precursor during transcription. This indicates that the 5'-terminal sequence of the cRNA is ppApGpC and that, therefore, ppApG most probably initiates transcription exactly at the 3' GpCpU(OH) terminus of the virion RNA templates. Virions were also tested for their ability to cap and methylate ppApG in the absence of transcription. No such activities were detected, whereas under the same conditions the vaccinia virus enzymes successfully capped and methylated this compound. Consequently, these experiments, together with those reported earlier, have not detected in influenza virions any capping and methylating enzymes active on the 5'-initiated termini of viral cRNA chains synthesized in vitro, whether these termini possess one, two, or three phosphates. Some mechanism for capping and methylation of viral cRNA must, however, exist, because the viral mRNA (cRNA) synthesized in the infected cell contains 5'-terminal methylated cap structures (Krug et al., J. Virol. 20:45-53, 1976). Possible mechanisms are discussed.
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PMID:Absence of detectable capping and methylating enzymes in influenza virions. 70 57


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