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)

Hepatitis E virus is responsible for both sporadic and epidemic hepatitis in developing countries. The nonenveloped virus is 27-34 nm in diameter and has been shown to contain a single-strand, positive-sense, polyadenylylated RNA genome of approximately 7.5 kilobases. The nucleotide sequence of the Burma strain of hepatitis E virus has been reported and three open reading frames (ORFs) have been identified. The deduced amino acid sequence from each of these ORFs was used to synthesize overlapping peptides (decamers overlapping at every fourth amino acid) on a solid phase. These peptides were then tested in an ELISA with pooled acute-phase sera from known cases of enterically transmitted non-A, non-B hepatitis collected in the Sudan. Linear B-cell epitopes were identified in all three ORFs. Epitopes were identified throughout the polyprotein encoded by ORF1, but they appeared to be particularly concentrated in the region of the RNA-dependent RNA polymerase. Distinct epitopes were identified in the presumed structural protein encoded by ORF2, and one epitope was identified close to the carboxyl terminus of the protein encoded by ORF3. These data precisely pinpoint linear B-cell epitopes recognized by antibodies from patients with acute hepatitis E and identify an antibody response directed against the RNA-dependent RNA polymerase.
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PMID:Human linear B-cell epitopes encoded by the hepatitis E virus include determinants in the RNA-dependent RNA polymerase. 137 90

The complete 5284-nucleotide sequence of the double-stranded RNA genome of Leishmania RNA virus 1 (LRV1) was determined and contains three open reading frames (ORFs) on the plus (+) (mRNA) strand. The predicted amino acid sequence of ORF3 has motifs characteristic of viral RNA-dependent RNA polymerases. ORF2, which may encode the major viral coat protein, overlaps ORF3 by 71 nucleotides, suggesting a +1 translational frameshift to produce a gag-pol type of fusion protein. Two alternative models for the frameshift are presented. The 5' splice leader sequence of kinetoplastid mRNAs is not in LRV1 RNA. This suggests that the 450-base region at the 5' end of the LRV1 (+)-strand, which contains ORF1 and is highly conserved among viral strains, does not encode protein but has a role in initiation of translation and/or RNA stability. The similarity of LRV1 genomic organization, replication cycle, and RNA-dependent RNA polymerase sequence to those of the yeast virus ScV L-A suggests a common ancestral origin. The possibility that LRV1 affects pathogenesis in leishmaniasis is intriguing.
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PMID:Molecular organization of Leishmania RNA virus 1. 138 95

The complete nucleotide sequence of apple stem grooving virus (ASGV) genome has been determined. The genome is 6496 nucleotides in length excluding a 3'-terminal poly(A) tail and contains two overlapping open reading frames (ORFs). ORF1 begins at nucleotide position 37 and is terminated at position 6341, encoding a protein with a molecular weight of 241 kDa. ORF2, which is in a different reading frame within ORF1, begins at position 4788 and can encode a 36-kDa protein. The 241-kDa protein contains two consensus sequences associated with the RNA-dependent RNA polymerase and the NTP-binding helicase. Comparisons of amino acid sequences around these conserved motifs with other RNA viruses revealed that ASGV has extensive similarities with apple chlorotic leaf spot, tymo-, carla-, and potexviruses, and is a member of the sindbis-like supergroup. ASGV coat protein is found to be located in the C-terminal region of the 241-kDa polyprotein. The 36-kDa protein encoded by ORF2 contains the consensus sequence Gly-Asp-Ser-Gly found in the active site of several cellular and viral serine proteases.
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PMID:The nucleotide sequence of apple stem grooving capillovirus genome. 141 30

The sequence of 6746 nucleotides representing the 3'-proximal half of the beet yellows closterovirus (BYV) genome was determined. In the direction 5' to 3', the sequence was composed of eight open reading frames (ORFs) potentially encoding proteins of 6.4K (ORF2), 65K (ORF3), 64K (ORF4), 24K (ORF5), 22K (ORF6), 20K (ORF7) and 21K (ORF8). An incomplete ORF, ORF1, encoded the C-terminal part of a putative RNA-dependent RNA polymerase, most closely related to polymerases of tricornaviruses; the putative product of ORF3, 65K, was found to be a homologue of the hsp70 family of cell heat-shock proteins. ORF2 potentially encoded a small hydrophobic 6.4K protein, apparently homologous to small hydrophobic proteins of potex- and carlaviruses. ORF6 encoded the viral coat protein, as indicated by its deduced Mr and amino acid composition. The products of ORFs 4, 5, 7 and 8 showed no significant similarities with protein sequences in the database and there are therefore no justifiable speculations concerning their possible functions. BYV RNA contains a 3'-terminal non-coding region of 181 nucleotides, with two stem-loop structures potentially folded within the 86 nucleotide sequence at the extreme 3' end. Analysis of the primary and secondary structure of this region together with the absence of aminoacylation and adenylylation in vitro showed that the BYV genome is devoid of a tRNA-like structure at its 3' end.
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PMID:Nucleotide sequence of the 3'-terminal half of beet yellows closterovirus RNA genome: unique arrangement of eight virus genes. 199 61

An 8-kilobase HindIII fragment carrying the histidase gene (hutH) and its regulatory region (hutP), from the Bacillus subtilis histidine utilization (hut) operon, was cloned in the temperate bacteriophage phi 105. Histidine utilization was restored in a hutH1 mutant by the specialized transducing phage (phi 105hutH11). The histidase gene in phi 105hutH11 was inducible and was shown to be under catabolite repression. The nucleotide sequence of 3,932 base pairs including the hutH and hutP loci revealed three open reading frames (ORFs). The molecular weights of ORF1 and ORF2 proteins were calculated to be 16,576 (151 amino acid residues) and 55,675 (508 amino acid residues), respectively. Reverse transcriptase mapping experiments showed that the putative promoter for the hut operon could be recognized by RNA polymerase sigma 43. The transcript starts at an adenosine residue 32 base pairs upstream from the initiation codon of ORF1. hutH+-transforming activity was found in ORF2, indicating that ORF2 encoded the histidase. A hutP1 mutation was determined as a substitution of an amino acid in ORF1. By using a specialized transducing phage containing the wild-type ORF1 gene, it was demonstrated that the presence of ORF1 protein in trans was absolutely required for the induction of the hut operon in a hutP1 mutant. These data strongly suggested that ORF1 encodes a positive regulator of the hut operon.
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PMID:Cloning and nucleotide sequences of histidase and regulatory genes in the Bacillus subtilis hut operon and positive regulation of the operon. 245 13

The genome of cowpea mottle virus (CPMoV) is a positive ssRNA of 4029 nucleotides with six major open reading frames (ORFs). A non-coding region of 34 nucleotides precedes the first AUG. ORF1 encodes a 25 kDa polypeptide of unknown function and ORF2 encodes a 56 kDa putative RNA replicase. Like other members of carmoviruses, suppression of the amber termination codon of ORF1 would produce a readthrough polypeptide of 83 kDa. ORF3 and ORF4 encode two small proteins of 7.8 and 9.8 kDa, respectively. ORF5 encodes the 40 kDa capsid protein. ORF6 is located within ORF5 but is in a different frame and has no postulated function. CPMoV RNA is blocked at the 5' end and is not polyadenylated at the 3' end. Comparison of the physicochemical properties, genomic arrangement, and predicted amino acid sequences with those of other viruses justify the assignment of CPMoV to the genus Carmovirus, family Tombusviridae.
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PMID:The nucleotide sequence of cowpea mottle virus and its assignment to the genus Carmovirus. 759 92

The nucleotide sequence of the 5'-end of feline calicivirus (FCV) Japanese F4 strain genome was determined. This region had 5311 bases and contained a large open reading frame (ORF1) encoding the non-structural proteins. The nucleotide sequence of the ORF1 region was highly conserved as compared with that of FCV F9 strain. When the deduced amino acid sequence of the ORF1 was compared with those of FCV F9 and CFI strains, the sequence was also highly conserved (88.9% and 88.8%, respectively). Functional motifs of the non-structural proteins were common to these strains. There were 2C polypeptide-, 3C cysteine protease- and 3D RNA-dependent RNA polymerase-like regions. The N-terminal region of 2C-like region continued upstream from the region identified by Neill [Virus Res. 17: 145-160]. Furthermore, the presence of 2B-like region was suggested in the upper stream of the 2C-like region, although the function of the region is unknown. When Kyte and Dolittle hydrophobicity profiles of the predicted amino acid sequences of the ORF1s of FCV F4 and F9 were computed and compared, both the profiles had striking similarities. In the region between residues 950-1000, there was a high rate of basic amino acid residues, suggesting that the polypeptide in this region of FCV may have a nucleic acid-binding function.
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PMID:The molecular cloning and sequence of an open reading frame encoding for non-structural proteins of feline calicivirus F4 strain isolated in Japan. 769 98

The double-stranded RNA genome of giardiavirus (GLV) has only two large open reading frame (ORFs). The 100-kDa capsid polypeptide (p100) is encoded by ORF1, whereas the only other viral polypeptide, the 190-kDa GLV RNA-dependent RNA polymerase (p190), is synthesized as an ORF1-ORF2 fusion protein by a (-1) ribosomal frameshifting. Edman degradation revealed that p100 was N-terminally blocked except for 2 to 5% of it that showed free N terminus starting from amino acid residue 33 of ORF1. Studies using antiserum targeted against amino acid residues 6 to 27 indicated that this region (NT) is absent from viral p100 and p190, while pulse-labelling experiments showed that NT is present in nascent p100 synthesized in GLV-infected Giardia lamblia but removed subsequently. In contrast, this region was retained in the two viral proteins synthesized in vitro, and it was not removed upon prolonged incubation or inclusion of microsomal fraction in the in vitro translation reaction mixtures. These results suggest that endoplasmic reticulum is not involved in the protein processing and that the precursors of p100 and p190 are incapable of cleaving themselves or each other. This specific cleavage was reproduced when lysates from GLV-infected G. lamblia were added, but not those from uninfected cells. The cleavage activity was relatively insensitive to phenylmethylsulfonyl fluoride, but it was inhibitable by leupeptin or E-64, two known specific inhibitors of cysteine protease. The possible origin of this processing activity is discussed.
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PMID:Maturation of giardiavirus capsid protein involves posttranslational proteolytic processing by a cysteine protease. 770 5

The complete nucleotide sequence of the genome of artichoke mottle crinkle virus (AMCV), a member of the tombusvirus group, has been determined. The genome is 4790 nucleotides (nt) in length. A full-length cDNA of the AMCV genome has been cloned in pUC9 downstream of the T7 RNA polymerase promoter. Transcripts were infective when inoculated onto Nicotiana clevelandii and N. benthamiana plants. The AMCV genome contains five open reading frames (ORFs). The first ORF from the 5' terminus (ORF1) encodes a protein with a predicted M(r) of 33K. ORF2 extends through the amber termination codon of ORF1 to yield a polypeptide of predicted M(r) 92K and which is the putative RNA-dependent RNA polymerase. ORF3 codes for the coat protein (41K). Two nested ORFs in different reading frames (ORFs 4 and 5) code for a 22K and a 19K polypeptide respectively. Sequence homologies suggest that the 22K protein could be involved in cell-to-cell movement of virus. ORFs 3, 4 and 5 are translated from two 3' coterminal subgenomic (sg) RNAs, the 5' termini of which have been mapped. The two sg RNAs are 2155 (sg1) and 934 (sg2) nt in length. ORF3 is expressed from sg1 RNA whereas ORFs 4 and 5 are potentially expressed from sg2 RNA. Time course experiments with Cynara scolymus protoplasts indicate that during AMCV infection both positive and negative strands of genomic and sg RNAs are produced and that sg2 RNA is produced before and at a higher level than sg1 RNA.
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PMID:Nucleotide sequence, genomic organization and synthesis of infectious transcripts from a full-length clone of artichoke mottle crinkle virus. 802 82

The 3'-terminal sequence of citrus tatter leaf virus lily isolate (CTLV-L) was determined from cloned cDNA. The sequence contains two open reading frames (ORFs). ORF1 encodes a protein that contains consensus sequences associated with the RNA-dependent RNA polymerase. ORF2, which is in a different reading frame within ORF1, can encode a 36 kD protein, putatively identified as a movement protein. CTLV-L coat protein (CP) was found to be located in the C-terminal region of the polyprotein encoded by ORF1. Evolutionary relationships and classification of capilloviruses is discussed.
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PMID:Nucleotide sequence of the 3'-terminal region of citrus tatter leaf virus RNA. 807 38


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