Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.26.9 (ribonuclease)
 6,589 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Two antigenic variants of visna virus were isolated sequentially from a single sheep inoculated with a plaque-purified strain of virus designated 1514. The genetically stable variants, LV1-1 and LV1-4, are of two classes: LV1-1 is partially neutralized by antibody to the inoculum strain 1514, while LV1-4 is not neutralized by antibody to 1514. The genetic mechanism responsible for generating the antigenic variants was investigated by comparing the chymotryptic and tryptic maps of the envelope glycoprotein gp135 and core polypeptides (p30, p16, p14), and by comparing the pattern of large oligonucleotides produced by digestion of the RNAs by T1 ribonuclease. We show that only the peptide maps of gp135 differ among strains, that the number of peptide fragments altered is small and that gp135 is the polypeptide that elicits neutralizing antibody. The maps of the RNAs are identical. We conclude that mutation in the glycoprotein gene rather than recombination is more probably responsible for antigenic variation, and speculate on the special aspects of visna virus replication relevant to this phenomenon.
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PMID:Antigenic variation in visna virus. 22 3

Two regions of amino acids homologous to the ribonuclease catalysis domain of the fungal RNases T2 of Aspergillus oryzae and Rh of Rhizopus niveus and the plant S-glycoproteins of Nicotiana alata are perfectly conserved in the amino acid sequence of the envelope glycoprotein E2 of classical swine fever virus (CSFV). To analyze the functional significance of these conserved sequences, the gene encoding E2 was inserted into the p10 locus of baculovirus and expressed in insect cells. Recombinant virus BacCE2 generated a protein which was similar in size (42 to 46 kDa) to wild-type E2 synthesized in swine kidney cells infected with CSFV. Recombinant E2 was purified by immunoaffinity chromatography from the lysate of cells infected with BacCE2 and assayed for RNase activity. RNase activity coeluted with the E2 fraction, indicating that ribonuclease activity is an inherent property of E2. The ribonuclease-specific activity of the protein fraction containing pure E2 was comparable to that of the N. alata S-glycoproteins.
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PMID:Glycoprotein E2 of classical swine fever virus: expression in insect cells and identification as a ribonuclease. 817 42

1. Elevated proinflammatory cytokines within the central nervous system (CNS) of individuals infected with human immunodeficiency virus (HIV) may contribute to altered CNS processes prior to the onset of AIDS. Most studies of HIV-induced alterations in cytokine expression within the CNS have focused on interleukin (IL)-1 and tumor necrosis factor (TNF). 2. We used a ribonuclease protection assay (RPA) to elucidate further the pattern of cytokine mRNA expression in the rat CNS in response to HIV envelope glycoprotein 160 (gp160). Male Sprague-Dawley rats were surgically implanted with a guide cannula directed into a lateral cerebral ventricle. HIV gp160 was injected intracerebroventricularly and rats were sacrificed immediately (time = 0) or at 1, 2, or 4 hr postinjection. Discrete brain regions were dissected, and peripheral glands removed. All tissues were frozen in liquid nitrogen until RNA extraction and assay. 3. IL-1beta IL-1alpha, TNF-alpha, and TNFbeta mRNAs were constitutively expressed in brain tissues. Central administration of gp160 dramatically increased mRNA expression for IL-1beta and TNFalpha in the hypothalamus, hippocampus, brainstem, and cerebellum. Furthermore, although mRNA expression for IL-5, IL-6, and IL-10 was never detected under basal conditions, these mRNAs were increased in brain tissue after administration of gp160. Peak expression in each brain region was detected 2 hr after administration. Multiple cytokine mRNAs were detected in peripheral tissues, but their expression was not altered by central administration of gp160. 4. Our results indicate that gp160 induces mRNA expression in brain for cytokines other than IL-1 and TNF. Screening for multiple cytokine mRNA in this manner provides extensive information concerning the particular cytokines that may be involved in HIV-induced pathologies and alterations in CNS processes.
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PMID:Human immunodeficiency virus glycoprotein 160 induces cytokine mRNA expression in the rat central nervous system. 1090 Dec 64

Bovine viral diarrhoea virus (BVDV) envelope glycoprotein E(rns) interacts with highly sulphated heparin-like glycosaminoglycans (GAGs) located on the cell surface as an early step in virus infection of cells. Site-directed mutagenesis of recombinant E(rns) was undertaken and analysis of mutants by heparin-affinity chromatography and cell surface binding showed that a cluster of basic amino acids (480KKLENKSK487) near the C terminus of E(rns) was essential for binding. Mutants with amino acid substitutions of lysine residues 481 and 485 in E(rns) reduced the binding of E(rns) to immobilized heparin and cellular GAGs but retained ribonuclease activity. In contrast to normal E(rns), E(rns) that was unable to bind to cells also failed to inhibit BVDV infection of cells when the cells were pre-incubated with E(rns). It is proposed that the cluster of basic residues (480KKLENKSK487) localized at the C-terminal end of E(rns) constitutes a GAG-binding site.
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PMID:Identification of the glycosaminoglycan-binding site on the glycoprotein E(rns) of bovine viral diarrhoea virus by site-directed mutagenesis. 1218 68

We searched human immunodeficiency virus (HIV) entry inhibitors and found a novel anti-HIV protein, actinohivin (AH), in a culture filtrate of the newly discovered genus actinomycete Longispora albida gen. nov., sp. nov. This paper deals with the mechanism of action of the anti-HIV activity of AH. AH exhibited potent anti-HIV activities against various strains of HIV-1 and HIV-2. AH bound to the glycoprotein gp120 of various strains of HIV-1 and gp130 of simian immunodeficiency virus (SIV), but did not bind to non-glycosylated gp120 nor to cells having CD4 and coreceptors, suggesting that AH inhibits viral entry to cells by binding to the envelope glycoprotein. The investigation of the effects of various sugars on AH-gp120 binding by ELISA revealed that yeast mannan alone strongly inhibited the binding (IC50 = 3.0 microg/ml). Experiments investigating the binding of AH to other glycoproteins revealed that AH binds to ribonuclease B and thyroglobulin that have a high-mannose type saccharide chain, but not to other glycoproteins having a N-glycoside type saccharide chain. The above results indicate that high-mannose type saccharide chains of gp120 are molecular targets of AH in its anti-HIV activity.
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PMID:Actinohivin, a novel anti-human immunodeficiency virus protein from an actinomycete, inhibits viral entry to cells by binding high-mannose type sugar chains of gp120. 1500 31

E(rns) is an envelope glycoprotein of classical swine fever virus (CSFV) with RNase activity. The purpose of this study was to produce an active E(rns) for further applications using the yeast secreted expression system. The E(rns) gene was cloned into the expression vector pGAPZalphaC which was introduced into Pichia pastoris. Expression of E(rns) protein in culture supernatant was confirmed by Western blot analysis using both the monoclonal antibody against CSFV E(rns) and CSFV-positive swine serum. The yeast-expressed E(rns) (yE(rns)) was shown to have N-linked glycosylation and to form homodimer of 74 kDa molecules. All monomer, homodimer, and deglycosylated forms of yE(rns) demonstrated intrinsic ribonuclease activity and a clear preference for uridine-rich sequence. A direct sandwich blocking enzyme-linked immunosorbent assay (ELISA) based on the yE(rns) was developed with a high sensitivity and specificity. The yE(rns) which possesses enzymatic activity and retains antigenicity may provide a useful material for developing a diagnostic kit.
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PMID:Secreted expression of the classical swine fever virus glycoprotein E(rns) in yeast and application to a sandwich blocking ELISA. 1621