Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Double Stranded RNA Viruses”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 325 records · Page 18Linked to original sources
PubMed2000

Phylogenetic analysis of some large double-stranded RNA replicons from plants suggests they evolved from a defective single-stranded RNA virus.

Sequences were recently obtained from four double-stranded (ds) RNAs from different plant species. These dsRNAs are not associated with particles and as they appeared not to be horizontally transmitted, they were thought to be a kind of RNA plasmid. Here we report that the RNA-dependent RNA polymerase (RdRp) and helicase domains encoded by these dsRNAs are related to those of viruses of the alpha-like virus supergroup. Recent work on the RdRp sequences of alpha-like viruses raised doubts about their relatedness, but our analyses confirm that almost all the viruses previously assigned to the supergroup are related. Alpha-like viruses have single-stranded (ss) RNA genomes and produce particles, and they are much more diverse than the dsRNAs. This difference in diversity suggests the ssRNA alpha-like virus form is older, and we speculate that the transformation to a dsRNA form began when an ancestral ssRNA virus lost its virion protein gene. The phylogeny of the dsRNAs indicates this transformation was not recent and features of the dsRNA genome structure and translation strategy suggest it is now irreversible. Our analyses also show some dsRNAs from distantly related plants are closely related, indicating they have not strictly co-speciated with their hosts. In view of the affinities of the dsRNAs, we believe they should be classified as viruses and we suggest they be recognized as members of a new virus genus (Endornavirus) and family (Endoviridae).

Defective Viruses↗
PubMed2006

Bluetongue virus and double-stranded RNA increase human vascular permeability: role of p38 MAPK.

Endothelial cell (EC) involvement in viral hemorrhagic fevers has been clearly established. However, virally activated mechanisms leading to endothelial activation and dysfunction are not well understood. Several different potential mechanisms such as direct viral infection, alterations in procoagulant/anticoagulant balance, and increased cytokine production have been suggested. We utilized a model of EC barrier dysfunction and vascular endothelial leakage to explore the effect of bluetongue virus (BTV), a hemorrhagic fever virus of ruminants, on human lung endothelial cell barrier properties. Infection of human lung EC with BTV induced a significant and dose-dependent decrease in trans-endothelial electrical resistance (TER). Furthermore, decreases in TER occurred in conjunction with cytoskeletal rearrangement, suggesting a direct mechanism for viral infection-mediated endothelial barrier disruption. Interestingly, double-stranded RNA (dsRNA) mimicked the effects of BTV on endothelial barrier properties. Both BTV- and dsRNA-induced endothelial barrier dysfunction was blocked by treatment with a pharmacological inhibitor of p38 MAPK. The induction of vascular permeability by dsRNA treatment or BTV infection was concomitent with induction of inflammatory cytokines. Taken together, our data suggest that the presence of dsRNA during viral infections and subsequent activation of p38 MAPK is a potential molecular pathway for viral induction of hemorrhagic fevers. Collectively, our data suggest that inhibition of p38 MAPK may be a possible therapeutic approach to alter viral-induced acute hemorrhagic diseases.

Bluetongue virus↗
PubMed1991

Characterization of a vaccinia virus-encoded double-stranded RNA-binding protein that may be involved in inhibition of the double-stranded RNA-dependent protein kinase.

The work described in this article identifies a vaccinia virus-encoded protein that may be involved in inhibition of the interferon-induced, double-stranded RNA-dependent protein kinase. Extracts prepared from vaccinia virus (WR strain)-infected cells contain an inhibitor of this kinase. Inhibition was reduced in extracts from which dsRNA-binding proteins had been removed by preadsorption to poly(rI).poly(rC)-Sepharose, suggesting that a dsRNA-binding protein may be involved in kinase inhibition. A single major virus-specific polypeptide of Mr = 25,000 (p25) bound to the poly(rI).poly(rC)-Sepharose. p25 was synthesized in a coupled in vitro transcription/translation system programmed with vaccinia cores, indicating that it is a vaccinia-encoded protein. Synthesis of p25 was detected at early times, by 2 hr post infection, peaked at 5 hours postinfection, and decreased during the late phase of virus replication. In the presence of cytosine arabinoside p25 synthesis did not decrease at late times postinfection. Kinase inhibitory activity accumulated with similar kinetics to p25, both in the presence and absence of cytosine arabinoside. Kinase inhibitory activity copurified with p25, through gel filtration, and Cibacron blue-affinity chromatography. Removal of p25 by precipitation with antiserum to p25 decreased kinase inhibitory activity in extracts prepared from vaccinia virus-infected cells. These results suggest that p25 may be necessary for the specific kinase inhibitory activity detected in vaccinia virus-infected cells.

Animals↗
PubMed1975

Replication of double-stranded RNA in particles of Penicillium stoloniferum virus S.

RNA polymerase activity was assayed in different particle classes of Penicillium stoloniferum virus S. RNA polymerase activity was found to be associated with H particles, which contain double-stranded RNA and single-stranded RNA, but not with L particles, which contain only double-stranded RNA and not with M particles, which contain only single-stranded RNA. In H particles the reaction occurred with the formation of one new molecule of double-stranded RNA (or two complementary single strands of RNA) per virus particle and the production of product particles (P particles), which contained two molecules of double-stranded RNA (or its equivalent). This RNA polymerase is therefore a replicase, which catalyses the synthesis of the two complementary strands of double-stranded RNA in a single virus particle. This is the first report of this type of RNA polymerase system.

Centrifugation, Density Gradient↗
PubMed1976

The induction of interferon by temperature-sensitive mutants of Sindbis virus: its relationship to double-stranded RNA synthesis and cytopathic effect.

Sindbis virus strain AR339 induces interferon by 3 h after infection at 39 degrees C and by 8 h after infection at 30 degrees C. The time course of interferon induction between 4 and 9 h after infection at the restrictive temperature (39 degrees C) was measured for 24 temperature-sensitive (ts) mutants, all of which induced interferon by 16 h after infection. Mutants showing total RNA synthesis at 39 degrees C greater than 10% of the wild-type level induced interferon with kinetics similar to the wild-type. Of those mutants showing 1 to 10% of the wild-type level of RNA synthesis at 39 degrees C, four induced interferon with kinetics similar to the wild type, whereas six showed a lag in induction. Nine mutants, showing 0 to 5% of the wild-type level of RNA synthesis at 39 degrees C, and the wild type, were examined for single and double-stranded RNA synthesis at 30 and 39 degrees C, using a combination of lithium chloride precipitation and CF11 cellulose chromatography. Six of these mutants showed a lag in interferon induction at 30 degrees C, while three showed no lag. For all nine mutants, double-stranded RNA synthesis at 39 degrees C was undetectable, although easily detectable for the wild type. Both the wild type and the mutants synthesized double-stranded RNA at 30 degrees C. For all mutants, time of interferon induction at 39 degrees C was correlated with c.p.e. as measured by trypan blue uptake 30 h after infection. The mutant F104, showing undetectable RNA synthesis and a long lag in interferon induction at 39 degrees C, was examined for interferon induction in a temperature shift system. Only 1/2 h at 30 degrees C, before a shift to 39 degrees C, was required for interferon to be induced with wil-type kinetics, and this was correlated with an increased c.p.e. 30 h after infection. Increased RNA synthesis and infectious virus production were detectable at 30 degrees C after an initial hour at 30 degrees C. It is concluded that, for interferon to be induced with normal kinetics, early virus functions are required, but that normal levels of double-stranded RNA synthesis are not necessary. The events which lead to interferon induction also lead to visible c.p.e.

Cell Line↗
PubMed1988

A virus with a bisegmented double-stranded RNA genome in rat (Oryzomys nigripes) intestines.

Examination of the intestinal contents of free-living Oryzomys nigripes rats by PAGE revealed two sharply defined bands that could be stained by ethidium bromide or by silver nitrate with comparable intensities. The molecules forming these bands were susceptible to digestion by pancreatic RNase A but not by RNase T1 or by DNase I. Their lengths were estimated to be about 2.6 and 1.5 kbp, respectively, by comparison with rotavirus SA11 genome segments. They cosedimented in CsCl gradients at a density of 1.39 to 1.40 g/ml, together with uniform particles approximately 35 nm in diameter with indistinct surface structure. It is suggested that these particles represent an as yet undescribed virus with a bisegmented double-stranded RNA genome, for which the name 'picobirnavirus' is proposed.

Animals↗
PubMed1992

Double-stranded and single-stranded RNA viruses of Saccharomyces cerevisiae.

Yeast RNA viruses include L-A (and its toxin-encoding satellites M1, M2, ...) and L-BC dsRNA viruses and the single-stranded replicons 20S RNA and 23S RNA. L-A has a single-segment 4.6-kb linear genome encoding a major coat protein (gag) and its RNA-dependent RNA polymerase (pol), the latter expressed as a gag-pol fusion protein formed by a -1 ribosomal frameshift. In vitro replication, transcription, and binding systems for L-A have been used to define cis sites necessary for packaging and replication of viral RNA. Cellular functions that promote viral replication include the MAK3-encoded N-acetyltransferase whose modification of the gag N terminus is necessary for L-A virus assembly. The toxins encoded by the M satellite RNAs are processed by enzymes (KEX1 and KEX2, for killer expression) whose study led to discovery of mammalian hormone-processing enzymes. 20S RNA is an apparently naked circular RNA replicon (with a dsRNA form called W) encoding a RNA polymerase-like molecule. Its copy number is induced 10,000-fold in 1% potassium acetate, and it is subject to the same SKI antiviral system that represses L-A, L-BC, and M dsRNA copy number.

Base Sequence↗
PubMed2004

Discovery of a dsRNA virus infecting the marine photosynthetic protist Micromonas pusilla.

We report the isolation of the first double-stranded (ds) RNA virus in the family Reoviridae that infects a protist (microalga Micromonas pusilla, Prasinophyceae). The dsRNA genome was composed of 11 segments ranging between 0.8 and 5.8 kb, with a total size of approximately 25.5 kb. The virus (MpRNAV-01B) could not be assigned to the genus level because host type, genome size, and number of segments smaller than 2 kb did not correspond to either of the two existing 11-segmented dsRNA genera Rotavirus and Aquareovirus. MpRNAV-01B has a particle size of 65-80 nm, a narrow host range, a latent period of 36 h, and contains five major proteins (120, 95, 67, 53, and 32 kDa). MpRNAV-01B was stable to freeze-thawing, resistant to chloroform, ether, nonionic detergents, chelating and reducing agents. The virus was inactivated at temperatures above 35 degrees C and by ionic detergent, ethanol, acetone, and acidic conditions (pH 2-5).

Chelating Agents↗
PubMed2001

Noncytopathic bovine viral diarrhea virus inhibits double-stranded RNA-induced apoptosis and interferon synthesis.

Bovine viral diarrhea virus (BVDV), a pestivirus of the Flaviviridae family, is an economically important cattle pathogen with a worldwide distribution. Both noncytopathic (ncp) and cytopathic (cp) biotypes of BVDV can be isolated from persistently infected cattle suffering from the lethal mucosal disease. The cp biotype correlates with the production of the NS3 nonstructural protein, which in the corresponding ncp biotype is present in its uncleaved form, NS23. Previously, we have shown that cp but not ncp BVDV induces the formation of alpha/beta interferons in bovine macrophages. In this study, we demonstrate that ncp BVDV inhibits the induction of apoptosis and the expression of interferon alpha/beta by poly(IC), a synthetic double-stranded RNA (dsRNA). Inhibition was observed only in cells which had been infected with ncp BVDV at least 12 h prior to the addition of dsRNA, which indicates that expression of viral proteins is necessary for the ncp virus to inhibit the effects of poly(IC). Additional experiments using transfected poly(IC) showed that ncp BVDV interfered with the intracellular action of dsRNA rather than with its uptake into the cells. Infected cells were not resistant to induction of apoptosis by actinomycin D or staurosporine, which suggests that ncp BVDV may specifically interfere with signaling through dsRNA. Interference with the innate antiviral host responses may explain the successful establishment of persistent infection by ncp BVDV in fetuses early in their development.

Animals↗
PubMed2006

Mouse hepatitis virus does not induce Beta interferon synthesis and does not inhibit its induction by double-stranded RNA.

Mouse hepatitis virus (MHV) does not induce interferon (IFN) production in fibroblasts or bone marrow-derived dendritic cells. In this report, we show that the essential IFN-beta transcription factors NF-kappaB and IFN regulatory factor 3 are not activated for nuclear translocation and gene induction during infection. However, MHV was unable to inhibit the activation of these factors and subsequent IFN-beta production induced by poly(I:C). Further, MHV infection did not inhibit IFN-beta production mediated by known host pattern recognition receptors (PRRs) (RIG-I, Mda-5, and TLR3). These results are consistent with the notion that double-stranded RNA, produced during MHV infection, is not accessible to cellular PRRs.

Animals↗
PubMed1992

Construction of a transducing virus from double-stranded RNA bacteriophage phi6: establishment of carrier states in host cells.

Bacteriophage phi 6 contains three double-stranded RNA (dsRNA) genomic segments. We have constructed a plasmid that contains a cDNA copy of the middle (M) segment, with a gene for kanamycin resistance (kan) inserted into the PstI site. A transcript of this cDNA was incorporated in vitro into procapsids along with natural transcripts of the S and L segments. The procapsids were coated with nucleocapsid surface protein P8 and transfected into Pseudomonas syringae pv. phaseolicola. The resulting infectious virus, phi 6 K1, was found to contain an M segment that was 1.2 kbp larger than the normal 4.1 kbp. K1 formed small, turbid plaques, and its genome was unstable. Preparations of K1 contained from about 0.1 to 10% large, clear-plaque forms of the virus which were usually missing the kan gene, and in some cases, the resulting segment M was smaller than its normal size. Cells picked from lawns of host cells infected with K1 yielded colonies that were resistant to kanamycin (Kan). These colonies could be passaged on kanamycin-containing medium. The cells were found to contain large amounts of dsRNA corresponding to the viral genomic segments. Some strains continued to produce viable phage, while others lost this ability. One strain completely lost the small genomic segment S. Approximately 1 in 10,000 infected cells acquired the carrier state with the original phage isolate K1. However, we isolated a viral mutant that was able to induce the carrier state in 10 to 20% of the infected cells. The ability to use drug resistance as a test for the carrier state makes this system very useful for the study of the mechanisms of induction of persistent infections.

Bacteriophages↗
PubMed1996

Organization and expression of the double-stranded RNA genome of Helminthosporium victoriae 190S virus, a totivirus infecting a plant pathogenic filamentous fungus.

The complete nucleotide sequence, 5178 bp, of the totivirus Helminthosporium vicotoriae 190S virus (Hv190SV) double-stranded RNA, was determined. Computer-assisted sequence analysis revealed the presence of two large overlapping ORFs; the 5'-proximal large ORF (ORF1) codes for the coat protein (CP) with a predicted molecular mass of 81 kDa, and the 3'-proximal ORF (ORF2), which is in the -1 frame relative to ORF1, codes for an RNA-dependent RNA polymerase (RDRP). Unlike many other totiviruses, the overlap region between ORF1 and ORF2 lacks known structural information required for translational frameshifting. Using an antiserum to a C-terminal fragment of the RDRP, the product of ORF2 was identified as a minor virion-associated polypeptide of estimated molecular mass of 92 kDa. No CP-RDRP fusion protein with calculated molecular mass of 165 kDa was detected. The predicted start codon of the RDRP ORF (2605-AUG-2607) overlaps with the stop codon (2606-UGA-2608) of the CP ORF, suggesting RDRP is expressed by an internal initiation mechanism. Hv190SV is associated with a debilitating disease of its phytopathogenic fungal host. Knowledge of its genome organization and expression will be valuable for understanding its role in pathogenesis and for potential exploitation in the development of biocontrol measures.

Amino Acid Sequence↗
PubMed1987

Isolation of a virus from Mycoplasma pulmonis.

A virus designated mycoplasma virus P1 has been isolated from Mycoplasma pulmonis. The virus infects M. pulmonis strain UAB 6510, and a plaque-forming unit assay has been developed. P1 has a tailed, polyhedral morphology with a head diameter of about 28 nm. Nucleic acid isolated from crude preparations of P1 virus contains double-stranded RNA, suggesting that P1 may be the first example of an RNA-containing mycoplasma virus.

Bacteriophages↗