Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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 complete nucleotide sequence of a virus infecting ornamental hibiscus (Hibiscus sp.) in Hawaii with symptoms of green ringspots on senescing leaves was determined from double-stranded RNA isolated from symptomatic tissue. Excluding polyadenylated regions at the 3' termini, the bipartite RNA genome was 8748 and 5019 nt in length for RNA1 and RNA2, respectively. The genome organization was typical of a cilevirus: RNA1 encoded a large replication-associated protein with methyltransferase, protease, helicase and RNA-dependent RNA polymerase domains as well as a 29-kDa protein of unknown function. RNA2 possessed five open reading frames that potentially encoded proteins with molecular masses of 15, 7, 62, 32, and 24 kDa. The 32-kDa protein is homologous to 3A movement proteins of RNA viruses; the other proteins are of unknown function. A proteome comparison revealed that this virus was 92 % identical to citrus leprosis virus cytoplasmic type 2 (CiLV-C2), a recently characterized cilevirus infecting citrus with leprosis-like symptoms in Colombia. The high sequence similarity suggests that the virus described in this study could be a strain of CiLV-C2, but since the new genus Cilevirus does not have species demarcation criteria established at present, the classification of this virus infecting hibiscus is open to interpretation. This study represents the first documented case of a cilevirus established in the United States and provides insight into the diversity within the genus Cilevirus.
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PMID:A cilevirus infects ornamental hibiscus in Hawaii. 2373 30

Rosellinia necatrix megabirnavirus 1 (RnMBV1) is a bi-segmented double-stranded RNA mycovirus that reduces the virulence of the fungal plant pathogen R. necatrix. We isolated strains of RnMBV1 with genome rearrangements (RnMBV1-RS1) that retained dsRNA1, encoding capsid protein (ORF1) and RNA-dependent RNA polymerase (ORF2), and had a newly emerged segment named dsRNAS1, but with loss of dsRNA2, which contains two ORFs of unknown function. Analyses of two variants of dsRNAS1 revealed that they both originated from dsRNA1 by deletion of ORF1 and partial tandem duplication of ORF2, retaining a much shorter 5' untranslated region (UTR). R. necatrix transfected with RnMBV-RS1 virions showed maintenance of virulence on host plants compared with infection with RnMBV1. This suggests that dsRNAS1 is able to be transcribed and packaged, as well as suggesting that dsRNA2, while dispensable for virus replication, is required to reduce the virulence of R. necatrix.
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PMID:Genome rearrangement of a mycovirus Rosellinia necatrix megabirnavirus 1 affecting its ability to attenuate virulence of the host fungus. 2450 94

The full-length genome sequence of a porcine picobirnavirus (PBV) detected in Italy in 2004 was determined. The smaller (S) genome segment was 1730 nt, coding for a putative RNA-dependent RNA polymerase. Two distinct subpopulations of larger (L) genome segment (LA and LB) were identified in the sample, with the sizes ranging from 2351 to 2666 nt. The ORF1, coding for a protein of unknown function, contained a variable number of repetitions of the ExxRxNxxxE motif. The capsid protein-coding ORF2 spanned nt 810-2447 in the LB variants and started at nt 734 in the LA variants. However, a termination codon was present only in one of all the LA segment variants. Three-dimensional modelling of the porcine PBV capsids suggested structural differences in the protruding domain, tentatively involved as antigens in the humoral immune response. Altogether, these findings suggest the simultaneous presence of two different PBV strains sharing the same S segment but displaying genetically diverse L segments. In addition, the sample probably contained a mixture of PBVs with aberrant RNA replication products. Altered structure in the L segments could be tolerated and retained in the presence of functionally integer-cognate genes and represents a mechanism of virus diversification.
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PMID:Genome sequencing identifies genetic and antigenic divergence of porcine picobirnaviruses. 2458 76

The sequences of five viral RNA segments of pigeonpea sterility mosaic virus (PPSMV), the agent of sterility mosaic disease (SMD) of pigeonpea (Cajanus cajan, Fabaceae), were determined using the deep sequencing technology. Each of the five RNAs encodes a single protein on the negative-sense strand with an open reading frame (ORF) of 6885, 1947, 927, 1086, and 1,422 nts, respectively. In order, from RNA1 to RNA5, these ORFs encode the RNA-dependent RNA polymerase (p1, 267.9 kDa), a putative glycoprotein precursor (p2, 74.3 kDa), a putative nucleocapsid protein (p3, 34.6 kDa), a putative movement protein (p4, 40.8 kDa), while p5 (55 kDa) has an unknown function. All RNA segments of PPSMV showed the highest identity with orthologs of fig mosaic virus (FMV) and Rose rosette virus (RRV). In phylogenetic trees constructed with the amino acid sequences of p1, p2 and p3, PPSMV clustered consistently with other emaraviruses, close to clades comprising members of other genera of the family Bunyaviridae. Based on the molecular characteristics unveiled in this study and the morphological and epidemiological features similar to other emaraviruses, PPSMV seems to be the seventh species to join the list of emaraviruses known to date and accordingly, its classification in the genus Emaravirus seems now legitimate.
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PMID:Deep sequencing of pigeonpea sterility mosaic virus discloses five RNA segments related to emaraviruses. 2468 74

Four novel double-stranded RNA molecules, named dsRNA 1 (5124 bp), dsRNA 2(1711 bp), dsRNA 3 (1423 bp) and dsRNA 4 (855 bp), were detected in strain HNHS-1 of Ustilaginoidea virens, the causal agent of rice false smut disease. Sequence analysis showed that the dsRNA1 contains two overlapping open reading frames (ORF) potentially encoding proteins with modest levels of sequence similarity to the coat protein (CP) and putative RNA-dependent RNA polymerase (RdRp), respectively, of viruses of the family Totiviridae. The deduced gene product of the ORF encoded by dsRNA2 is homologous to putative RdRp of viruses in the family Partitiviridae; the ORF encoded by dsRNA3 shares some similarity to a hypothetical protein with unknown function. It is noteworthy that the dsRNA4 lacked integrated ORFs. Isomeric viral particles of about 40 nm in diameter were observed by transmission electron microscopy in a mycelium tissue preparation of strain HNHS-1-R1, a single-spore subculture of strain HNHS-1 containing only the dsRNA1 segment. Phylogenetic analysis and examination of the organization of the two putative RdRp sequences both indicated that there are at least two novel virus species present in strain HNHS-1. We named the two novel viruses Ustilaginoidea virens RNA virus 2 and Ustilaginoidea virens partitivirus 4, respectively.
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PMID:Detection and sequence analysis of two novel co-infecting double-strand RNA mycoviruses in Ustilaginoidea virens. 2493 86

Here we report a biological and molecular characterization of a novel positive-sense RNA virus isolated from a field isolate (NW10) of a filamentous phytopathogenic fungus, the white root rot fungus that is designated as Rosellinia necatrix fusarivirus 1 (RnFV1). A recently developed technology using zinc ions allowed us to transfer RnFV1 to two mycelially incompatible Rosellinia necatrix strains. A biological comparison of the virus-free and -recipient isogenic fungal strains suggested that RnFV1 infects latently and thus has no potential as a virocontrol agent. The virus has an undivided positive-sense RNA genome of 6286 nucleotides excluding a poly (A) tail. The genome possesses two non-overlapping open reading frames (ORFs): a large ORF1 that encodes polypeptides with RNA replication functions and a smaller ORF2 that encodes polypeptides of unknown function. A lack of coat protein genes was suggested by the failure of virus particles from infected mycelia. No evidence was obtained by Northern analysis or classical 5'-RACE for the presence of subgenomic RNA for the downstream ORF. Sequence similarities were found in amino-acid sequence between RnFV1 putative proteins and counterparts of a previously reported mycovirus, Fusarium graminearum virus 1 (FgV1). Interestingly, several related sequences were detected by BLAST searches of independent transcriptome assembly databases one of which probably represents an entire virus genome. Phylogenetic analysis based on the conserved RNA-dependent RNA polymerase showed that RnFV1, FgV1, and these similar sequences are grouped in a cluster distinct from distantly related hypoviruses. It is proposed that a new taxonomic family termed Fusariviridae be created to include RnFV1 and FgV1.
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PMID:A novel single-stranded RNA virus isolated from a phytopathogenic filamentous fungus, Rosellinia necatrix, with similarity to hypo-like viruses. 2510 Oct 66

Recent studies have demonstrated that a diverse array of mycoviruses infect the plant pathogenic fungus Sclerotinia sclerotiorum. Here, we report the molecular characterization of a newly identified mycovirus, Sclerotinia sclerotiorum fusarivirus 1 (SsFV1), which was isolated from a sclerotia-defective strain JMTJ14 of S. sclerotiorum. Excluding a poly (A) tail, the genome of SsFV1 comprises 7754 nucleotides (nts) in length with 83 and 418 nts for 5'- and 3'-untranslated regions, respectively. SsFV1 has four non-overlapping open reading frames (ORFs): ORF1 encodes a 191 kDa polyprotein (1664 amino acid residues in length) containing conserved RNA-dependent RNA polymerase (RdRp) and helicase domains; the other three ORFs encode three putative hypothetical proteins of unknown function. Phylogenetic analysis, based on RdRp and Helicase domains, indicated that SsFV1 is phylogenetically related to Rosellinia necatrix fusarivirus 1 (RnFV1), Fusarium graminearum virus-DK21 (FgV1), and Penicillium roqueforti RNA mycovirus 1 (PrRV1), a cluster of an independent group belonging to a newly proposed family Fusarividae. However, SsFV1 is markedly different from FgV1 and RnFV1 in genome organization and nucleotide sequence. SsFV1 was transmitted successfully to two vegetatively incompatible virus-free strains. SsFV1 is not responsible for the abnormal phenotype of strain JMTJ14.
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PMID:Molecular Characterization of a Novel Positive-Sense, Single-Stranded RNA Mycovirus Infecting the Plant Pathogenic Fungus Sclerotinia sclerotiorum. 2600 96

Nigrospora oryzae is a pathogen that can infect plants of various species. Here, we report the isolation of a novel mycovirus from N. oryzae infecting rice, as well as the complete genome sequence and genomic organization of this virus, which we have named "Nigrospora oryzae nonsegmented RNA virus 1" (NoNRV1). The genome of NoNRV1 contained two non-overlapping open reading frames (ORF1 and ORF2) potentially encoding a protein with an unknown function in ORF1 and a putative RNA-dependent RNA polymerase (RdRp) in ORF2. Homology and phylogenetic analysis revealed that NoNRV1 was most similar to the Ustilaginoidea virens nonsegmented virus 1 (UvNV-1) and distantly related to members of the virus family Partitiviridae. It is proposed that NoNRV1, together with UvNV-1 and other related viruses, might represent a novel virus taxon of mycoviruses belonging to a partitivirus-like lineage.
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PMID:A novel nonsegmented double-stranded RNA mycovirus identified in the phytopathogenic fungus Nigrospora oryzae shows similarity to partitivirus-like viruses. 2649 81

The alternaria blackspot of rapeseed is one of the most prominent diseases of rapeseed. It is caused by three species of the genus Alternaria: Alternaria brassicicola, Alternaria brassicae, and Alternaria raphanin. Here we report a novel positive-sense RNA virus from an A. brassicicola strain 817-14. The virus has a 6639 nucleotide (nt) long genome, excluding a poly (A)-tail, and was predicted to contain three putative open reading frames (ORF1, ORF2, and ORF3). The large ORF1 encoded a 174-kDa polyprotein (composed of 1522 amino acid residues) containing a conserved RNA-dependent RNA polymerase (RdRp) domain and a helicase domain. The other two smaller ORFs encoded polypeptides with unknown function. Homology search and phylogenetic analysis, based on the RdRp and helicase domains, suggest that this virus is related to and grouped with Sclerotinia sclerotiorum fusarivirus 1 (SsFV1), Rosellinia necatrix fusarivirus 1 (RnFV1), Fusarium graminearum virus-DK21 (FgV1), and Penicillium roqueforti RNA mycovirus 1 (PrRV1), all of which belong to a newly proposed family Fusariviridae. For this study, we designed the virus as "Alternaria brassicicola fusarivirus 1" (AbFV1). Virus elimination revealed that AbFV1 has no conspicuous impact on the biological properties of its host.
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PMID:Characterization of a novel single-stranded RNA virus, closely related to fusariviruses, infecting the plant pathogenic fungus Alternaria brassicicola. 2670 21

In this study, we report the discovery and molecular characterization of a novel mycovirus, Nigrospora oryzae fusarivirus 1 (NoFV1) isolated from the rice-infecting fungus Nigrospora oryzae. Excluding a poly (A) tail, the genome of the virus is 7004 nucleotide (nt) long containing three putative nonoverlapping open reading frames (ORF1, ORF2, and ORF3). The large ORF1 encodes a polypeptide with a conserved RNA-dependent RNA polymerase (RdRp) domain and a helicase domain that functions for RNA replication. Each of the smaller ORF2 and the smallest ORF3 encodes a putative protein with an unknown function. Amino acid (aa) sequence similarities between the NoFV1-ORF1- and ORF2-encoded proteins and the homologous sequences from other mycoviruses were found. Phylogenetic analysis on the basis of the RdRp and helicase domains showed that NoFV1 is phylogenetically related to viruses in the newly proposed family Fusariviridae. Thus, we suggest that NoFV1 might be a novel member of family Fusariviridae.
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PMID:A novel fusarivirus isolated from the phytopathogenic fungus Nigrospora oryzae. 2741 60


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