Biomedical subjects

A G Solovyev

Publications and source records attributed to A G Solovyev.

25 records · Page 2Linked to original sources

PubMed1994

Genome characterization and taxonomy of Plantago asiatica mosaic potexvirus.

The complete nucleotide sequence of Plantago asiatica mosaic virus (P1AMV) genomic RNA has been determined. The 6128 nucleotide sequence contains five open reading frames (ORFs) coding for proteins of M(r) 156K (ORF1), 25K (ORF2), 12K (ORF3), 13K (ORF4) and 22K (ORF5). The sequences of these P1AMV proteins exhibit strong homology to the proteins of the other potexviruses. Phylogenetic trees based on the multiple sequence alignments of three conserved domains in ORF1 product and capsid protein reveal a close relationship of P1AMV to papaya mosaic virus and clover yellow mosaic virus. The P1AMV genomic RNA and a major subgenomic RNA (sgRNA) of 0.9 kb have been detected in infected leaves by Northern blot hybridization. The latter sgRNA is the messenger for virus capsid protein and its 5' terminus has been located 23 nucleotides upstream of the initiator codon of the coat protein gene. The P1AMV virion RNA and RNA transcript resembling the 0.9 kb sgRNA have been translated in vitro giving rise to a single major 170K product and a major 22K product, respectively.

Amino Acid Sequence↗

PubMed1994

Restriction fragment length polymorphism analysis of reverse transcription-PCR products reveals the existence of two major strain groups of beet necrotic yellow vein virus.

Beet necrotic yellow vein virus (BNYVV)-infected sugarbeets were obtained from many parts of Europe and also from some sites in Asia and the U.S.A. Reverse transcription (RT)-PCR products of more than 1 kbp were obtained for four different regions of the viral genome which may be particularly important with respect to the pathogenic properties of the virus, i.e. for the coat protein and the 42K protein-encoding regions on RNA 2 and for major parts of RNAs 3 and 4. Restriction fragment length polymorphism (RFLP) patterns obtained with these PCR products revealed the existence of two major strain groups of BNYVV, named type A and type B. The A type was detected in Greece, the former Yugoslavia, Slovakia, parts of Austria, Italy, Spain, parts of France, Belgium, The Netherlands and England as well as in Asia (Turkey, Kazachstan, China and Japan) and the U.S.A. The B type occurs in Germany and parts of France. Mixed infections were detected at the borderline regions between areas of the A and B types. Comparisons of published and newly determined nucleotide sequences of the respective parts of the BNYVV genome indicate that the percentage of nucleotide differences between the A and the B type is approximately 3% for the respective regions of RNAs 2 and 3 and approximately 1.5% for RNA 4. Nucleotide sequences appear to be remarkably stable within each of the two strain groups. The majority of the nucleotide differences between the A and B types occur in the third triplet position. The amino acid changes in the coat protein area are outside the four previously determined antigenic regions that are accessible on the surface of the virus particles and are involved in the formation of continuous and presumably also discontinuous epitopes. This may explain why serological differences between the two strain groups have not been found.

Base Sequence↗

PubMed1993

A novel open reading frame in tobacco mosaic virus genome coding for a putative small, positively charged protein.

From sequence comparisons between the tobramovirus genomes an open reading frame (ORF-X) potentially encoding a small, positively charged protein (33- to 45-amino-acids long) was found to overlap the immediate 3' and 5' sides of the transport protein gene and coat protein gene, respectively. In vitro translation of the monocistronic artificial transcripts generated with T7 RNA polymerase yielded a protein of M(r) 4000 (p4) and an unexpected trypsin-sensitive complex of M(r) 54,000 that was resistant to reduction with 2-mercaptoethanol but could be dissociated by 8 M urea. Assembly of this complex was inhibited completely by site-directed mutagenesis within a conserved, positively charged 5-amino-acid long segment of the ORF-X protein. After centrifugation in low salt buffer the 54-kDa complex remained mostly associated with ribosomes. Apparently this complex represents a specific aggregate of the p4 product of ORF-X with a protein of approximate M(r) 50,000 that is a component of the translation apparatus.

Amino Acid Sequence↗

PubMed1993

Effects of sequence elements in the potato virus X RNA 5' non-translated alpha beta-leader on its translation enhancing activity.

The 5' non-translated alpha beta-leader sequence of potato virus X RNA consists of two regions: the alpha sequence (41 nucleotides with no G) and the beta sequence (42 nucleotides upstream from AUG). The alpha beta-leader has been shown to enhance strongly the expression of adjacent genes in chimeric mRNAs. This phenomenon has been postulated to be due to the unpaired conformation of the 5'-terminal 30 nucleotides and/or to the presence within the alpha region of the CCACC pentanucleotide complementary to the 3'-terminal conserved structure of 18S rRNA. Different derivatives of alpha beta-leader have been constructed for use in determining the contribution of separate elements of the alpha beta sequence to translational enhancement. It was found that deletion of the alpha sequence large fragment which was supposed to be unfolded did not reduce the delta alpha beta-leader enhancement activity. Moreover, translational enhancement was greater for this derivative. Deletion of the beta sequence resulted in a considerable increase in activity of the alpha-leader showing that the beta region was dispensable for translation. Disruption or 'masking' of CCACC led to inactivation of the alpha beta-leader as a translational enhancer. Thus, we identified the CCACC pentanucleotide as the primary motif responsible for the translation enhancing ability of alpha beta-leader.

Base Sequence↗

PubMed1992

Translation enhancing properties of the 5'-leader of potato virus X genomic RNA.

The double-stranded DNA copy corresponding to the 5'-nontranslated alpha beta-leader of potato virus X (PVX) genomic RNA (positions -3 to-85 according to AUG initiator) was chemically synthesized and fused to the transcription plasmids containing three different reporter genes: neomycinphosphotransferase type II (NPT II) gene, Bacillus thuringiensis coleopteran-specific toxic protein gene and beta-glucuronidase (GUS) gene. Expression of the reporter genes in vitro and in plant protoplasts (in the case of GUS gene) reveals that the alpha beta-leader of PVX RNA acts as a translation enhancer despite the presence of the upstream vector-derived sequence and irrespective of the length of the spacer sequence preceding the reporter genes.

Animals↗

PubMed1991

In vitro membrane binding of the translation products of the carlavirus 7-kDa protein genes.

Two double-stranded DNA copies of the genes potentially coding for the 7-kDa proteins of potato virus M (PVM) and potato virus S (PVS) were synthesized and cloned into T7 transcription vectors. Cell-free translation of the corresponding monocistronic transcripts yielded in both cases a single protein of approximately 7-8 kDa that contains a highly hydrophobic N-terminal segment. To analyze their membrane-binding potential, both proteins were synthesized in the membrane-enriched Krebs-2 extract. It was found that the smooth membrane fraction was enriched in the carlavirus 7-kDa proteins. The primary and predicted secondary structures of their N-terminal hydrophobic segments suggest that the latter can function as signals for translocation into the rough endoplasmic reticulum.

Amino Acid Sequence↗

PubMed1991

Expression strategy of the potato virus X triple gene block.

The mode of expression of the overlapping genes of the triple block positioned internally in potato virus X (PVX) RNA was examined. The results of In vitro translation of synthetic RNA transcripts and natural PVX-specific methylmercuric hydroxide-denatured dsRNAs suggest that the 25K protein is expressed as a single translation product of the 2.1 kb subgenomic (sg) RNA and that both the 12K and 8K proteins are expressed from the same 1.4 kb sgRNA.

Base Sequence↗