Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.27.5 (RNase)
 17,967 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The structure of the ribonucleoprotein (RNP) complex of three coronaviruses was investigated. A single-stranded helix of diam. 14 to 16 nm and up to 320 nm in length was released from disrupted particles of human coronavirus strain 229E and mouse hepatitis virus strain 3 after incubation in mild conditions. The helical complexes appeared to be composed of globular subunits with long axes of 5 to 7 nm surrounding a hollow core of diam. 3 to 4 nm. The complexes were shown to be sensitive to both pancreatic RNase and to pronase. No undegraded internal component was obtained from disrupted avian infectious bronchitis virus particles. We conclude that these structures are RNP complexes. The similarity between these RNPs and those of other large lipid containing RNA viruses is discussed.
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PMID:Ribonucleoprotein-like structures from coronavirus particles. 20 20

We examined the synthesis of intracellular RNA in primary chicken embryo kidney cells infected with the avian coronavirus infectious bronchitis virus. Infected cells were labeled with (32)P(i) in the presence of actinomycin D for the duration of the viral multiplication cycle, and nucleic acids were extracted, denatured, and analyzed on agarose slab gels. Six major RNA species were found. None of these RNAs was found in extracts of mock-infected cells. All six of the virus-specified RNAs (designated species A through F) were single stranded, and RNA species F had the same electrophoretic mobility as purified viral genome RNA. The molecular weights of the five subgenomic RNAs were estimated to be 0.8 x 10(6), 0.9 x 10(6), 1.3 x 10(6), 1.5 x 10(6), and 2.6 x 10(6) for species A through E, respectively. All of the RNAs were polyadenylated and are therefore likely to be viral mRNA's. The RNAs were synthesized in approximately constant proportions throughout the viral multiplication cycle. Intracellular RNA species A, B, C, D, and F and the purified viral genome were analyzed by RNase T(1) fingerprinting. The results confirmed the identification of RNA species F as the intracellular genome and the derivation of the four smaller RNAs from the genome. Fingerprinting also showed that the intracellular RNAs constitute a nested set such that the nucleotide sequence of each RNA is contained within all larger RNAs and each larger RNA contains an additional sequence congruent with its greater size. Finally, the possible modes of transcription and translation of the infectious bronchitis virus RNAs are discussed.
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PMID:Coronavirus multiplication strategy. I. Identification and characterization of virus-specified RNA. 624 5

The ribonucleoprotein (RNP) of avian infectious bronchitis virus (IBV) was examined by electron microscopy after shadowing with carbon/platinum. Linear RNP strands up to 6.7 microns in length, from three IVB strains, were sensitive to both pancreatic RNase and to proteases. These strands were obtained from spontaneously disrupted complete particles but not from disrupted incomplete particles that lacked RNP. They were also released from Nonidet P40-disrupted particles and could be isolated on sucrose density gradients at a density of 1.27 g/ml. In some cases, helical RNP complexes associated with virus particles were observed that were similar to RNPs of human coronavirus strain 229E and mouse hepatitis virus strain 3.
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PMID:Ribonucleoprotein of avian infectious bronchitis virus. 626 41

The presence of subgenomic mRNAs (sgRNAs) in virions of infectious bronchitis virus was examined by probing Northern blots of RNA extracted from virions using as a probe a cDNA of the 3'-terminal nucleocapsid protein (N) gene. The sgRNAs were readily detected even after extensive purification of virions and after RNase A treatment of virions. The molar ratio of gRNA to each sgRNA was in the range 25 to 400 for IBV-M41 and 10 to 30 for IBV-Beaudette. After comparison with the molar ratios of genomic to intracellular viral sgRNAs it was estimated that the efficiency of incorporation of gRNA into virions was approximately 100 to 500-fold greater than for sgRNAs in the case of M41 and 20 to 100-fold for Beaudette, depending on the sgRNA species. It is concluded that sgRNAs can be present within IBV virions. Approximately 1 in 3 Beaudette virions and 1 in 20 M41 particles might contain a single copy of one sgRNA.
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PMID:Analysis of messenger RNA within virions of IBV. 820 18

Genomic RNA fingerprints of infectious bronchitis virus (IBV) strains M41 and Conn46 were prepared to identify T1 RNase-resistant oligonucleotides 'unique' to each of the two IBV strains. Such oligonucleotides were subsequently eluted from the gels and their nucleotide sequences determined. When oligonucleotide probes of those sequences were synthesized and used in a dot-blot hybridization assay, the probes lacked IBV strain-specificity and reacted with the RNAs of homologous as well as heterologous IBV strains. Based on these results, the methods used in this study need to be applied to a large number of oligonucleotide probes, to find one or a few that might be suitable as IBV strain- or serotype-specific oligonucleotide probes.
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PMID:Oligonucleotide probes in infectious bronchitis virus diagnosis and strain identification. 839 Apr 75

Epidemiological studies have indicated that exposure to elevated levels of particulate matter exacerbates several pulmonary diseases, including asthma, bronchitis, and viral infections. Respiratory syncytial virus (RSV) is the major cause of bronchiolitis and pneumonia in infants and may lead to the development of asthma in childhood. To determine whether particle exposure modulates the immune response to RSV, eight-week-old female BALB/c mice received an intratracheal (i.t.) instillation of either 40 micro g ultrafine carbon black (CB) particles or vehicle. The following day, mice were i.t. instilled with either 106 pfu RSV or uninfected media. End points were examined 1, 2, 4, 7, and 10 days during RSV infection. Compared with RSV alone, tumor necrosis factor-alpha (TNF-alpha) protein was reduced in the bronchoalveolar lavage fluid (BALF) on days 1 and 2 of infection; there was also a reduction in BALF lymphocyte numbers on day 4, which correlated with reductions in both IFN-gamma-inducible protein (IP-10), lymphotactin, and IFN-gamma mRNAs in the lungs of RSV + CB mice. Multiprobe ribonuclease protection assays of RSV + CB lung tissue showed no changes in the RSV-associated chemokines regulated upon activation, normal T cell expressed and secreted (RANTES), eotaxin, monocyte chemoattractant protein (MCP-1), macrophage inflammatory protein (MIP)-1 alpha or MIP-1 beta. Viral titers in RSV + CB mice were lower than RSV on days 2-4 of infection. By day 7 of infection, however, neutrophil numbers, proinflammatory cytokine mRNA expression, and protein levels of TNF-alpha and the Th2 cytokine interleukin (IL)-13 were increased in the lungs of RSV + CB mice, indicating an exacerbation of infection. These data indicate that preexposure to ultrafine particles induces an inflammatory milieu promoting allergic immune responses rather than IFNgamma production necessary for microbial defense.
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PMID:Effect of preexposure to ultrafine carbon black on respiratory syncytial virus infection in mice. 1266 Mar 65