PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “RNA virus”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

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

At least 19 recordsLinked to original sources
PubMed1989

A mutation in the short 5'-proximal open reading frame on Rous sarcoma virus RNA alters virus production.

The 5'-proximal open reading frame on Rous sarcoma virus RNA encodes a seven-amino-acid peptide and is conserved in all avian sarcoma-leukosis retroviruses. Ribosome-binding site analysis in intact chick cells showed that the 5'-proximal AUG codon is a strong site for initiation of translation in vivo. Removal of the 5'-proximal AUG codon by site-specific mutagenesis resulted in a virus with a reduced ability either to replicate or to transform a population of chicken embryo fibroblasts. These results establish a procedure for determining sites of ribosome binding and initiation of translation on mRNAs in intact eucaryotic cells and strongly suggest that the 5'-proximal open reading frame (or its AUG codon) on Rous sarcoma virus RNA has an important role in regulating viral activity.

Animals↗
PubMed1975

Bleomycin: action on growth of oncogenic RNA viruses and on cell transformation.

Bleomycin (BLM) inhibits cell proliferation of noninfected chick embryo fibroblasts by blocking their DNA synthesis selectively. Chick embryo fibroblasts have beentransformed by Schmidt-Ruppin D strain of Rous Sarcoma Virus. Transformation has been determined by a focus assay. Foci formation is strongly reduced by BLM. Virus replication is inhibited by BLM in growing and confluent monolayer cells. This result might be explained by the observation that this drug reduces proliferation of growing and of confluent monolayer cells very sensitively. During the first 24 hours after infection the BLM inhibitory effect is more pronounced than in the case of BLM-application during the period 24--48 hours after infection. This result is explained by published results, showing that cell division is required only for the intitiation of transcription of virus RNA but not for its maintenance. BLM has only little effect on virus growth in transformed cells, because in these cells initiation of transcription of virus RNA has already taken place before the drug was added. From the data obtained it is concluded, that BLM inhibits growth of Rous Sarcoma Virus by blocking cell proliferation.

Animals↗
PubMed1977

Configuration of tobacco mosaic virus, RNA during virus assembly.

When TMV reassembles, the uncoated RNA is folded back along the growing rod, probably down the central hole. This surprising configuration is essential for rapid elongation--presumably supplying RNA to its site of incorporation while keeping the bulk of the free RNA out of the way.

Kinetics↗
PubMed1991

Negative strand RNA viruses come of age. Negative Strand RNA Virus Transcription and Replication sponsored by the Fundación Juan March, Madrid, Spain, April 22-24, 1991.

The recent development of several systems that facilitate manipulation of the nucleotide sequences of negative strand RNA viruses and examination of the effects of these changes in vivo has enabled great progress in the study of these fascinating organisms. Such studies are leading to a greater understanding of the role of viral nucleotide sequences and viral (and sometimes cellular) proteins in the control of negative strand RNA virus replication and transcription. This Fundación Juan March Workshop provided an excellent opportunity for extensive discussion and exchange of ideas on just how far the research on these viruses has gone, and for contemplating the paths that future inquiries will take.

RNA Viruses↗
PubMed2025

Argonaute 2 targets viral transcripts but not genomes of RNA viruses during antiviral RNA interference in Drosophila.

RNA interference (RNAi) mediated by the small interfering RNA (siRNA) pathway is a major antiviral mechanism in insects. This pathway is triggered when double-stranded RNA (dsRNA) produced during virus replication is recognized by Dicer-2, leading to the formation of virus-derived siRNA duplexes. These siRNAs are loaded onto the programmable nuclease Argonaute-2 (AGO2), with one strand serving as a guide to target and cleave fully complementary sequences of viral RNAs. While siRNAs are generated from viral dsRNA, the specific viral RNA species targeted for silencing during RNA virus replication remains unclear. In this study, we characterized the primary viral RNA targets of the Drosophila siRNA pathway during infections caused by negative and positive RNA viruses, namely Vesicular stomatitis virus (VSV) and Sindbis virus (SINV). Our findings reveal that polyadenylated transcripts of VSV and SINV are the major targets of silencing by the siRNA pathway during infection, likely when they are poised for translation. Consistent with earlier findings, we show that AGO2 is associated with ribosomes in control and virus infected cells. Therefore, we propose that the inhibition of the replication of RNA viruses in Drosophila results from the silencing of incoming viral transcripts, facilitated by the association of AGO2 with ribosomes.

Animals↗
PubMed1986

Ambisense RNA viruses: positive and negative polarities combined in RNA virus genomes.

The coding strategies of arenaviruses (family Arenaviridae) and members of the Phlebovirus genus of the Bunyaviridae differ from those of other negative-sense RNA viruses in that some proteins are coded in viral-complementary RNA sequences and others are coded in the viral RNA sequence. The term ambisense RNA has been proposed to denote these unique coding arrangements. The implications of the ambisense RNA coding strategy for the evolution and infection processes of these viruses are discussed.

Arenaviridae↗
PubMed1992

Transcription of a recombinant influenza virus RNA in cells that can express the influenza virus RNA polymerase and nucleoprotein genes.

A new transfection system for influenza virus was developed using the clone 76 cell line, in which the viral RNA polymerase and nucleoprotein (NP) genes can be expressed in response to dexamethasone. Ribonucleoprotein (RNP) complexes were reconstituted by expressing proteins from a chimeric NS-chloramphenicol acetyltransferase (CAT) RNA consisting of the full-length negative-strand RNA of the CAT gene positioned between the 5'- and 3'-terminal sequences of influenza virus RNA segment 8, and purifying NP from an NP gene-expressing Escherichia coli strain. When the reconstituted RNP was transfected into clone 76 cells, CAT was produced only when the synthesis of the three RNA polymerase subunits and NP was induced by treatment with dexamethasone.

Animals↗
PubMed1977

Strandedness of Pichinde virus RNA.

The Pichinde virus RNA did not possess the following characteristics of eucaryotic mRNA: polyadenylic acid sequence, capped methylated structure, and ability to direct protein synthesis in vitro. Polysomal RNA extracted from cells infected with Pichinde virus reannealed with 32P-labeled virus RNA, protecting about 60% of the latter against RNase degestion. The polyadenylic acid-containing polysomal RNA also reannealed to the 32P-labeled virus RNA to approximately the same extent. These indicate that the major part of the genomic RNA of Pichinde virus is negative stranded.

Arenaviruses, New World↗
PubMed1989

Detection of rabies virus RNA in the central nervous system of experimentally infected mice using in situ hybridization with RNA probes.

Rabies virus is usually demonstrated in human or animal tissues using antigen-detection or viral isolation techniques. Rabies virus RNA can be demonstrated in paraffin-embedded tissues using in situ hybridization. Negative (-) sense 35S- and 3H-labeled RNA probes, specific for rabies virus nucleocapsid protein mRNA, were used for the detection of rabies virus RNA in the nervous system of mice experimentally infected with fixed and street strains of rabies virus. In situ hybridization signals were compared with rabies virus antigen demonstrated with immunoperoxidase staining. Rabies virus RNA and antigen were also demonstrated in the same neurons using a double-labeling technique. In situ hybridization has potential applications as a diagnostic test for rabies and in studies of rabies pathogenesis.

Animals↗
PubMed1976

The 30S Moloney sarcoma virus RNA contains leukemia virus nucleotide sequences.

The 50S-70S RNA of a Moloney sarcoma-leukemia virus [Mo-MSV(MLV)] complex produced by a particular mouse cell line was shown by gel electrophoresis to contain a major (97%) 30S sarcoma-specific subunit species and a minor (3%) 38S leukemia virus-specific subunit. On the basis of its sedimentation coefficient and known complexity, the 30S Mo-MSV RNA was estimated to be a unique RNA molecule of about 6000 nucleotides. Hybridization experiments using viral RNA and DNA complementary to viral RNA (cDNA) made by viral DNA polymerase indicated that the 30S Mo-MSV RNA shared 70% of its sequences with Mo-MLV, 30% with another MLV derived from Mo-MLV, and 30% with Kirsten sarcoma-xenotropic leukemia virus. The 30S Mo-MSV RNA sequences shared with these viruses were not additive. The Tm of a Mo-MSV RNA-MLV cDNA hybrid was 83 degrees C, indicating that large contiguous nucleotide sequences were shared between the two nucleic acids. Mo-MSV RNA and Mo-MLV RNA shared possibly seven of 20-30 RNAase T1-resistant oligonucleotides, while Mo-MSV RNA contained three, and Mo-MLV RNA contained at least five specific oligonucleotides. We conclude that the 30S Mo-MSV RNA molecule consists of approximately 70% (about 4200 nucleotides) Mo-MLV-specific sequences and of 30% (1800 nucleotides) Mo-MSV-specific sequences covalently linked. Our results favor the hypothesis that 30S Mo-MSV RNA was generated by recombination between Mo-MLV and other genetic elements. We discuss whether all or only the MSV-specific sequences of the 30S Mo-MSV RNA function as sarcoma genes. Mo-MLV cDNA was hybridized about 45% by unfractionated Mo-MSV (MLV) RNA at RNA/DNA ratios of up to 10, about 50% by electrophoretically purified 30S Mo-MSV RNA at RNA/DNA ratios up to 500, but close to 100% by unfractionated Mo-MSV(MLV) RNA at RNA/DNA ratios over 900. This indicated that unfractionated RNA of our Mo-MSV(MLV) contained a complete complement of Mo-MLV, albeit at a low ratio.

Base Sequence↗
PubMed1991

Properties of human parainfluenza virus type 3 RNA polymerase/replicase activity in vitro: consensus with other negative-stranded RNA viruses.

A cell-free system supporting transcription, replication, and nucleocapsid assembly of the genome RNA of human parainfluenza virus type 3 (HPF3) is described. Cytoplasmic extracts from infected CV-1 or BHK cells catalyzed the transcription of the entire HPF3 genome, the replication of genome RNA, and the assembly of this RNA into nucleocapsidlike structures. Newly replicated RNA was resistant to micrococcal nuclease digestion and was stable in CsCl gradients, exhibiting the density of authentic HPF3 nucleocapsids. After fractionation of the extracts, the nucleocapsid-containing pellet fraction synthesized viral mRNAs. Reconstitution with the soluble protein fraction was necessary for genome RNA replication and nucleocapsid assembly.

Animals↗
PubMed1992

Examples of expression systems based on animal RNA viruses: alphaviruses and influenza virus.

Successful recovery of RNA viruses and functional RNA replicons from cDNA has greatly facilitated molecular genetic analyses of viral proteins and cis-regulatory elements. This technology allows the use of RNA virus replication machinery to express heterologous sequences. Both positive-strand and negative-strand animal RNA viruses have been engineered to produce chimeric viruses expressing protective epitopes from other pathogens and for transient expression of heterologous sequences.

Alphavirus↗
PubMed1979

The effect of pyrophosphate analogues on influenza virus RNA polymerase and influenza virus multiplication.

Analogues of pyrophosphate have been tested as inhibitors of influenza virus-RNA polymerase activity in cell-free assays. The most active compound, phosphonoformic acid (PFA), reduced the polymerase activity to 50 per cent at a concentration of 20 muM. The inhibition was dependent on the type of divalent cation present in the assay. PFA at a concentration of 400 muM also inhibited the influenza virus plaque formation by 90 per cent.

DNA-Directed RNA Polymerases↗
PubMed1985

Rational design of vaccines against enveloped RNA viruses.

The enveloped RNA viruses are responsible for many important infectious diseases both in the UK and worldwide. The most familiar of these would probably be influenza, measles, mumps, rubella, rabies, dengue and yellow fever. Conventional vaccines against all of the most widespread diseases have been available for several years, although with widely varying degrees of safety and efficacy. Although vaccines against diseases such as measles, rubella, and yellow fever have been fairly successful, all vaccines against diseases caused by this group of viruses still have several drawbacks and are in need of improvement for a variety of reasons. During the past decade our knowledge in several diverse areas of the biological sciences has expanded to the extent that it can now be combined and serious attempts made to design and engineer biological molecules with immunogenic potential. First, significant advances have been made in elucidating the mechanisms operating in the immune defence network and in determining the structure of both immunogenic molecules and the components of the immune system with which they interact. Second, the development of recombinant DNA technology has enabled biological molecules to be synthesized under conditions not restricted by the characteristics of their parent organism. Such molecules can then be altered in such a way as to improve their efficiency and their level of production. It is the purpose of this paper to outline the problems associated with the production of vaccines against enveloped RNA viruses and to discuss how recent advances in knowledge and techniques can help to overcome these problems.

Antigen-Presenting Cells↗
PubMed1989

Variability and evolution of the plant RNA virus pepper mild mottle virus.

The RNA genomes of 26 isolates of pepper mild mottle virus were compared by their RNase T1 fingerprints. Twenty-three isolates came from epidemic outbreaks in greenhouse-grown peppers in Almería (southeastern Spain) from 1983 to 1987; three other isolates, from 1980, came from Sicily (Italy) and Zaragoza (central Spain). The 26 fingerprints can be classified into 10 different types; nucleotide substitution rates show them to be very similar. Cluster and cladistic analyses group types corresponding to the Almería isolates separate from those of 1980. Intraannual and interannual nucleotide differences were estimated. An evolutionary model for pepper mild mottle virus built on these data indicates a highly stable population, maintaining its diversity through time, with a main prevailing haplotype from which closely related variants arise that do not replace it. This high stability could be due to strong functional constraints on variation, as suggested by the high proportion of invariant versus polymorphic sites in fingerprints.

Biological Evolution↗