Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.7.48 (transcriptase)
 9,479 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The genome of pineapple mealybug wilt-associated closterovirus-2 (PMWaV-2) was cloned from double-stranded RNA isolated from diseased pineapple and its sequence determined. The 3'-terminal 14861 nt of the single-stranded RNA genome contains ten open reading frames (ORFs) which, from 5' to 3', potentially encode a >204 kDa polyprotein containing papain-like protease, methyltransferase and helicase domains (ORF1a), a 65 kDa RNA-dependent RNA polymerase (ORF1b), a 5 kDa hydrophobic protein (ORF2), a 59 kDa heat shock protein 70 homologue (ORF3), a 46 kDa protein (ORF4), a 34 kDa coat protein (ORF5), a 56 kDa diverged coat protein (ORF6), a 20 kDa protein (ORF7), a 22 kDa protein (ORF8) and a 6 kDa protein (ORF9). A 132 nt untranslated region was present at the 3' terminus of the genome. This genome organization is typical of the monopartite closteroviruses, including the putative +1 ribosomal frameshift allowing expression of ORF1b. Phylogenetic analysis revealed that within the family CLOSTEROVIRIDAE: the mealybug-transmitted PMWaV-2 is more closely related to other mealybug-transmitted members than to those which are transmitted by aphids or whiteflies. Within this group, PMWaV-2 shares the greatest sequence identity with grapevine leafroll-associated virus-3, another mealybug-transmitted closterovirus.
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PMID:Nucleotide sequence, genome organization and phylogenetic analysis of pineapple mealybug wilt-associated virus-2. 1112 51

This study reports the first sequence of a flexuous rod-shaped mycovirus and also the first molecular characterization of a virus that infects the plant-pathogenic fungus BOTRYTIS: cinerea. The mycovirus BOTRYTIS: virus F (BVF) contains an ssRNA genome of 6827 nucleotides and a poly(A) tract at or very near the 3' terminus. Computer analysis of the genomic cDNA sequence of BVF revealed two potential open reading frames (ORFs) encoding proteins of 212 kDa (ORF1) and 32 kDa (ORF2). ORF1 showed significant sequence identity to the RNA-dependent RNA polymerase (RdRp)-containing proteins of plant 'tymo-' and 'potex-like' viruses. However, the ORF1 protein contained an opal putative readthrough codon between the helicase and RdRp regions, a feature not seen in this position in 'tymo-' and 'potex-like' replicases sequenced to date. ORF2 shared amino acid similarity with coat proteins of plant 'potex-like' viruses. Three untranslated regions were present in the genome, comprising a region of 63 nucleotides preceding the initiation codon of ORF1, a 93 nucleotide stretch between ORFs 1 and 2 and a 3'-terminal region of 70 nucleotides preceding the poly(A) tract. The nucleotide sequence of a putative defective RNA (D-RNA) of 829 nucleotides was also determined. The D-RNA contained one potential ORF comprising the N-terminal region of the replicase fused in-frame to the C-terminal region of the coat protein. It is proposed that the mycovirus BVF belongs to a new, as yet unassigned genus in the plant 'potex-like' virus group.
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PMID:Genome characterization of Botrytis virus F, a flexuous rod-shaped mycovirus resembling plant 'potex-like' viruses. 1112 60

Replication of Alfalfa mosaic virus (AMV) RNAs depends on the virus-encoded proteins P1 and P2. P1 contains methyltransferase- and helicase-like domains, and P2 contains a polymerase-like domain. Coimmunoprecipitation experiments revealed an interaction between in vitro translated-P1 and P2 and showed that these proteins are present together in fractions with RNA-dependent RNA polymerase activity. A deletion analysis in the yeast two-hybrid system showed that in P1 the C-terminal sequence of 509 amino acids with the helicase domain was necessary for the interaction. In P2, the sequence of the N-terminal 241 aa was required for the interaction. In infected protoplasts, P1 and P2 colocalized at a membrane structure that was identified as the tonoplast (i.e., the membrane that surrounds the vacuoles) by using a tonoplast intrinsic protein as a marker in immunofluorescence studies. While P1 was exclusively localized on the tonoplast, P2 was found both at the tonoplast and at other locations in the cell. As Brome mosaic virus replication complexes have been found to be associated with the endoplasmic reticulum (M. A. Restrepo-Hartwig and P. Ahlquist, J. Virol. 70:8908-8916, 1996), viruses in the family Bromoviridae apparently select different cellular membranes for the assembly of their replication complexes.
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PMID:Alfalfa mosaic virus replicase proteins P1 and P2 interact and colocalize at the vacuolar membrane. 1116 Jun 87

The complete nucleotide sequence of the hop latent virus (HpLV) genome was determined. The viral RNA genome is 8,612 nucleotides long, excluding the poly(A) tail, and contains six open reading frames (ORFs), which encode putative proteins of 224-kDa (ORF 1), 25-kDa (ORF 2), 11-kDa (ORF 3), 7-kDa (ORF 4), 34-kDa (ORF 5), and 12-kDa (ORF 6). ORF 5 encodes the coat protein as demonstrated by N-terminal sequencing of three proteolytic peptides derived from the virus particle. The genome organization of HpLV is similar to that of other species in the genus Carlavirus, and the overall sequence of HpLV is more similar to that of Potato virus M than to sequences of other carlaviruses reported to date. The amino acid sequences of the putative methyltransferase, RNA helicase, and RNA-dependent RNA polymerase encoded in ORF 1 and an 'accessory' helicase encoded in ORF 2 of the HpLV genome were compared with those of viruses in the 'tymo' lineage: the genera Carlavirus, Potexvirus, Allexivirus, Foveavirus, Trichovirus, Capillovirus, Vitivirus, and Tymovirus. The phylogenetic relationships among the viruses in these genera are discussed. This is the first molecular characterization of a carlavirus infecting hop plants.
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PMID:Molecular characterization of Hop latent virus and phylogenetic relationships among viruses closely related to carlaviruses. 1120 2

Turnip yellow mosaic virus (TYMV) encodes a 206-kDa (206K) polyprotein with domains of methyltransferase, proteinase, NTPase/helicase, and RNA-dependent RNA polymerase (RdRp). In vitro, the 206K protein has been shown to undergo proteolytic processing, giving rise to the synthesis of 140-kDa (140K) and 66-kDa (66K) proteins, the latter comprising the RdRp protein domain. Antibodies were raised against the 66K protein and were used to detect the corresponding viral protein in infected cells; both leaf tissues and protoplasts were examined. The antiserum specifically recognized a protein of approximately 66 kDa, indicating that the cleavage observed in vitro is also functional in vivo. The 66K protein accumulates transiently during protoplast infection and localizes to cellular membrane fractions. Indirect immunofluorescence assays and electron microscopy of immunogold-decorated ultrathin sections of infected leaf tissue using anti-66K-specific antibody revealed labeling of membrane vesicles located at the chloroplast envelope.
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PMID:Detection and subcellular localization of the turnip yellow mosaic virus 66K replication protein in infected cells. 1122 99

The dengue virus RNA-dependent RNA polymerase, NS5, and the protease/helicase, NS3, are multidomain proteins that have been shown to interact both in vivo and in vitro. A hyperphosphorylated form of NS5 that does not interact with NS3 has been detected in the nuclei of virus-infected cells, presumably as the result of the action of a functional nuclear localization sequence within the interdomain region of NS5 (residues 369-405). In this study, it is shown by using the yeast two-hybrid system that the C-terminal region of NS3 (residues 303-618) interacts with the N-terminal region of NS5 (residues 320-368). Further, it is shown that this same region of NS5 is also recognized by the cellular nuclear import receptor importin-beta. The interaction between NS5 and importin-beta and competition by NS3 with the latter for the same binding site on NS5 were confirmed by pull-down assays. The direct interaction of importin-beta with NS5 has implications for the mechanism by which this normally cytoplasmic protein may be targetted to the nucleus.
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PMID:A small region of the dengue virus-encoded RNA-dependent RNA polymerase, NS5, confers interaction with both the nuclear transport receptor importin-beta and the viral helicase, NS3. 1125 77

The complete nucleotide (nt) sequence of a Singapore isolate of broad bean wilt fabavirus from Megakepasma erythrochlamys L., designated BBWV-ME, was determined. Its bipartite genome consisted of two positive-sense single-stranded ribonucleic acids (RNA). RNA1 (5951 nt in length) encoded a putative protease cofactor, nucleotide triphosphate (NTP)-binding domain (helicase), viral genome-linked protein (VPg), protease and RNA-dependent RNA polymerase (RdRp). RNA2 (3607 nt in length) encoded a putative movement protein (MP) and coat proteins (CP). Genome organization of BBWV-ME was similar to other viruses in the Comoviridae family. Phylogenetic analyses showed that fabaviruses were more closely related to the comoviruses than the nepoviruses.
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PMID:Complete sequences and phylogenetic analyses of a Singapore isolate of broad bean wilt fabavirus. 1126 7

Our research is directed towards enhancing the understanding of the molecular biology of dengue virus replication with the ultimate goal being to develop novel antiviral strategies based on preventing critical inter- or intra-molecular interactions required for the normal virus life cycle. The viral RNA-dependent RNA polymerase (NS5) and the viral helicase (NS3) interaction offers a possible target for inhibitors to bind and prevent replication. In this study the yeast-two hybrid system was used to show that a small region of NS5 interacts with NS3, and also with the cellular nuclear transport receptor importin-beta. Furthermore, intramolecular interaction between the two putative domains of NS5 can also be detected by the yeast two-hybrid assay. We have also modified the colony lift assay for the beta-galactosidase reporter activity in intact yeast cells which reflects the strength of interaction between two proteins to a microtiter plate format. This assay offers a unique opportunity to screen for small molecule compounds that block physiologically important interactions.
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PMID:Characterisation of inter- and intra-molecular interactions of the dengue virus RNA dependent RNA polymerase as potential drug targets. 1134 63

The complete nucleotide sequence of Citrus leaf blotch virus (CLBV) was determined. CLBV genomic RNA (gRNA) has 8747 nt, excluding the 3'-terminal poly(A) tail, and contains three open reading frames (ORFs) and untranslated regions (UTR) of 73 and 541 nucleotides at the 5' and 3' termini, respectively. ORF1 potentially encodes a 227.4-kDa polypeptide, which has methyltransferase, papain-like protease, helicase, and RNA-dependent RNA polymerase motifs. ORF2 encodes a 40.2-kDa polypeptide containing a motif characteristic of cell-to-cell movement proteins. The 40.7-kDa polypeptide encoded by ORF3 was identified as the coat protein. The genome organization of CLBV resembles that of viruses in the genus Trichovirus, but they differ in various aspects: (i) in trichoviruses ORF2 overlaps ORFs 1 and 3, whereas in CLBV, ORFs 2 and 3 are separated and ORFs 1 and 2 overlap in one nucleotide; (ii) CLBV gRNA and CP are larger than those of trichoviruses; and (iii) the CLBV 3' UTR is larger than that of trichoviruses. Phylogenetic comparisons based on CP amino acid signatures clearly separates CLBV from trichoviruses. Also contrasting with trichoviruses, CLBV could not be transmitted to Chenopodium quinoa Willd. Considering these singularities, we propose that CLBV should be included in a new virus genus.
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PMID:The nucleotide sequence and genomic organization of Citrus leaf blotch virus: candidate type species for a new virus genus. 1150 57

Hepatitis-splenomegaly (HS) syndrome is an emerging disease in chickens in North America; the cause of this disease is unknown. In this study, the genetic identification and characterization of a novel virus related to human hepatitis E virus (HEV) isolated from bile samples of chickens with HS syndrome is reported. Based upon the similar genomic organization and significant sequence identity of this virus with HEV, the virus has been tentatively named avian HEV in order to distinguish it from human and swine HEV. Electron microscopy revealed that avian HEV is a non-enveloped virus particle of 30-35 nm in diameter. The sequence of the 3' half of the viral genome ( approximately 4 kb) was determined. Sequence analyses revealed that this genomic region contains the complete 3' non-coding region, the complete genes from open reading frames (ORFs) 2 and 3, the complete RNA-dependent RNA polymerase (RdRp) gene and a partial helicase gene from ORF 1. The helicase gene is the most conserved gene between avian HEV and other HEV strains, displaying 58-61% aa and 57-60% nt sequence identities. The RdRp gene of avian HEV shares 47-50% aa and 52-53% nt sequence identities and the putative capsid gene (ORF 2) of avian HEV shares 48-49% aa and 48-51% nt sequence identities with the corresponding regions of other known HEV strains. Phylogenetic analysis indicates that avian HEV is genetically related to, but distinct from, other known HEV strains. This discovery has important implications for HEV animal models, nomenclature and natural history.
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PMID:Genetic identification and characterization of a novel virus related to human hepatitis E virus from chickens with hepatitis-splenomegaly syndrome in the United States. 1156 38


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