Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.7.6 (RNA polymerase)
 34,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Purified preparations of molluscum contagiosum virus contain a DNA-dependent RNA polymerase (EC 2.7.7.6) with similar but not identical properties to those of the enzyme found in vaccinia virions. The ultraviolet inactivation kinetics of the RNA polymerase from both viruses were similar, displaying fast and slow components. Ultraviolet irradiation destroyed the interfering capacities of molluscum and inactivated vaccinia virions, and the interferon-inducing capacity of molluscum virus slowly and with first-order kinetics. Inactivation studies of the interferon-inducing capacity of vaccinia virus were complicated by cytotoxic effects. Electron microscopical studies showed all stages of virus growth in vaccinia-infected mouse embryo cells; molluscum virus appeared to be degraded in lysosome-like bodies. In preliminary studies, marked changes in cytoplasmic RNA synthesis and in patterns of polypeptide synthesis were found in vaccinia-infected but not in molluscum-infected mouse embryo cells.
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PMID:Molluscum contagiosum -- a defective poxvirus? 1 Dec 75

The DNA-dependent RNA polymerase (DdRP) is an essential enzyme for transcription of molluscum contagiosum virus (MCV), a member of the family Poxviridae which replicates in the cytoplasm of the infected cell. Using PCR technology and oligonucleotide primers, corresponding to two conserved domains (RQP[T/S]LH and NADFDGDE) of known largest subunits of eucaryotic and procaryotic DNA-dependent RNA polymerases, the DdRP gene of the genome of molluscum contagiosum virus type 1 (MCV-1) was identified and characterized. The oligonucleotide primers were designed according to the coding usage statistics of known open reading frames of the viral genome. The gene for the largest subunit of DdRP was localized within the DNA sequences of a part of the BamHI DNA fragment A (BamHI/HindIII DNA fragment A8a; 13.5 kbp, 0.454 to 0.525 viral map units) of the MCV-1 genome. The DNA nucleotide sequence analysis of a part (6709 bp) of this DNA fragment revealed the presence of 12 open reading frames (ORFs). It was found that ORF-4 (nucleotide position (NP) 2586 to 6452) and ORF-1 (NP 1192 to 1752) encode two polypeptides comprising 1289 (147 kDa) and 187 (22 kDa) amino acid residues, respectively. The comparative analysis of the amino acid sequences of these ORFs to the amino acid sequences of two subunits (RPO1, 147 kDa and RPO6, 22 kDa) of the DdRP of vaccinia virus revealed high amino acid sequence identity/similarity of about 71.9/21.5% and 46.5/39.6%, respectively. In addition it was found that the putative gene position of ORF-11, which is located on the lower strand between the loci of the ORF-1 and ORF-4 (NP 4256 to 4657, 134 aa, 15 kDa), is similar to the genomic arrangement of the J5L protein of vaccinia virus and L5L of variola virus. The value of amino acid sequence identity/similarity between the product of ORF-11 and the corresponding gene of vaccinia virus (J5L) was found to be 43.2/28.8%. The analysis of the amino acid sequence deduced from ORF-3 (NP 261 to 1289, 343 aa, 40 kDa), which is located upstream from the locus of the RPO6 of the MCV-1 genome, showed significant identity/similarity (47.5/35.7%) to the amino acid sequence of the 40-kDa subunit of the poly(A) polymerase (PAP2) of vaccinia virus. The arrangement of the identified loci of the PAP2, RPO6, ORF-11, and RPO1 of the genome of MCV-1 shows that this particular genomic region of the mollucsum contagiosum virus and vaccina virus is colinear.
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PMID:Identification and properties of the genes encoding the poly(A) polymerase and a small (22 kDa) and the largest subunit (147 kDa) of the DNA-dependent RNA polymerase of molluscum contagiosum virus. 761 82

Adenosine N1-oxide (ANO) is a potent and highly selective inhibitor of vaccinia virus replication. We examined the impact of ANO on vaccinia virus macromolecular synthesis during synchronous infection of BSC40 cells. Viral DNA replication and viral late protein synthesis were blocked completely by ANO, effects that were attributable to a defect in the expression of viral early genes. Vaccinia virus early proteins were not synthesized in the presence of ANO, even though vaccinia virus early mRNAs were produced. Cellular protein synthesis was unaffected by ANO, and virus infection in the presence of the drug did not elicit the normal shutoff of host protein synthesis. Adenosine N1-oxide triphosphate (ANO-TP), the predominant metabolite of the drug in vivo, could substitute for ATP in RNA synthesis by purified vaccinia virus RNA polymerase. ANO-TP could support early transcription by purified virions if dATP was provided as an energy source. ANO-TP did not inhibit early transcription in the presence of ATP. These findings suggest a novel antiviral mechanism whereby incorporation of a modified nucleotide into viral mRNAs might selectively block viral gene expression at the level of translation. We believe that ANO merits consideration as an antipoxvirus drug for topical treatment of molluscum contagiosum in humans.
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PMID:Adenosine N1-oxide inhibits vaccinia virus replication by blocking translation of viral early mRNAs. 766 36

The DNA-dependent RNA polymerase (DdRP or RNAP) is an essential enzyme of transcription of replicating systems of prokaryotic and eukaryotic organisms as well as cytoplasmic DNA viruses. DdRPs are complex multisubunit enzymes consisting of 8-14 subunits, including two large subunits and several smaller polypeptides (small subunits). An extensive search between the amino acid sequences of the known largest subunit of DNA-dependent RNA polymerases (RPO1) of different organisms indicates that all these polypeptides possess a universal heptapeptide NADFDGD in domain D. All RPO1 harbor a second well-conserved hexapeptide RQP(TS)LH upstream (26-31 amino acids) of the universal motif. The genes encoding the largest subunit of DdRP of insect iridescent virus type 6 (IIV6), fish lymphocystis disease virus (LCDV), and molluscum contagiosum virus (MCV-1), all members of the group of cytoplasmic DNA viruses, were identified by PCR technology. With the exception of IIV6, all other viral RPO1 possess the two C-terminal conserved regions G and H. The lack of C-terminal repetitive heptapeptide (YSPTSPS), which is a common feature of the largest subunit of eukaryotic RNAPII, is an additional characteristic of RPO1 proteins of LCDV and of MCV-1. All viral RPO1 proteins were found to be lacking the amino acid N at a distinct position in domain F. This amino acid is known to be highly conserved in alpha-amanitin-sensitive eukaryotic RNA polymerases II. Comparison of the amino acid sequences of the RPO1 polypeptides of IIV6, LCDV, and MCV-1 with the corresponding prokaryotic, eukaryotic, and viral proteins revealed differences in amino acid similarity and phylogenetic relationships. IIV6 RPO1 possesses the closest similarity to the homologous subunit of eukaryotic RNAPII and lower but also significant similarity to that of eukaryotic RNAPI and RNAPIII, archaeal, eubacterial, and viral polymerases. The similarity between RPO1 of IIV6 and the cellular polymerase subunits is consistently higher than to the RPO1 of other cytoplasmic DNA viruses, for example, vaccinia and variola virus, African swine fever virus (ASFV), and MCV-1. The RPO1 of LCDV shows the highest similarity to the RPO1 of IIV6 and significant lower similarity to the eukaryotic polymerases II and III as well as to the archaebacteral subunit. However, it is still considerably more similar to the cellular polymerase subunits than to the homologous viral proteins. The RPO1 of IIV6 possesses more similarity to cellular polymerases than the complete RPO1 of LCDV, indicating that there is a substantial difference in the organization of the RPO1 genes between these members of two genera of the Iridoviridae family. Analysis of the MCV-1 RPO1 revealed high amino acid homologies to the corresponding polypeptides of vaccinia and variola virus. The viral RPO1 proteins, including vaccinia and variola virus, MCV-1, ASFV, IIV6, and LCDV, share the common feature of showing the highest similarity to the largest subunit of eukaryotic RNAPII than to that of RNAPI, RNAPIII, and RPO1 of archaebacterias, eubacterias, ASFV, IIV6, and LCDV. Evolution of the individual largest subunit of DdRPs was tentatively investigated by generating phylogenetic trees using multiple amino acid alignments. These indicate that the RPO1 proteins of IIV6 and LCDV might have evolved from the largest subunit of eukaryotic RNAPII after divergence from the homologous subunits of RNAPI and RNAPIII. In contrast, evolutionary development of the RPO1 of vaccinia and variola virus, MCV-1, and ASFV seems to be quite different, with their common ancestor diverging from cellular homologues before the separation of the three types of eukaryotic ploymerases and having probably diverged earlier from their common lineage with cellular proteins.
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PMID:Evolution of viral DNA-dependent RNA polymerases. 882 52

Molluscum contagiosum virus (MCV) and vaccinia virus (VV) are serologically unrelated poxviruses with a disparate genome composition (MCV, 66% G+C; VV, 33% G+C). Molecular studies of MCV have been hindered by the inability to propagate the virus in cells cultured in vitro. We sequenced 7765 bp of MCV DNA cloned from four widely spaced regions throughout the MCV genome and identified a total of 11 potential open reading frames (ORF), designated CX1-11. These include MCV homologues of the VV genes encoding protein kinase 2, structural protein VP8, RNA polymerase 35 kDa subunit and 3beta-hydroxysteroid dehydrogenase. The position and orientation of the MCV ORFs was collinear to the VV genome, with the exception of the region around ORF CX11 which is inverted in the MCV genome.
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PMID:Similarity in genome organization between Molluscum contagiosum virus (MCV) and vaccinia virus (VV): identification of MCV homologues of the VV genes for protein kinase 2, structural protein VP8, RNA polymerase 35 kDa subunit and 3beta-hydroxysteroid dehydrogenase. 900 Jan 5

Molluscum contagiosum virus (MCV), a member of the family Poxviridae, replicates well in vivo but cannot be propagated in cell culture. The coding capacity of the MCV genome was previously determined by DNA nucleotide sequence analysis. The objective of the present study was to establish experimental systems for the identification and characterization of early MCV gene transcripts. MCV mRNA was obtained in three ways: (1) MCV early mRNA was synthesized in vitro using permeabilized virions, (2) MCV mRNA was extracted from MCV-infected skin tissue, and (3) MCV mRNA was extracted from MCV-infected human embryonic fibroblasts. RNA/DNA hybridization experiments showed significant early transcriptional activity in two parts of the MCV genome. Transcripts of 11 early MCV genes located in these parts of the genome, including two subunits of the MCV DNA-dependent RNA polymerase (mc077R and mc079R), the MCV poly(A)+ polymerase gene (mc076R), and the MCV MHC class I homolog (mc080R), were detected in reverse transcription-polymerase chain reaction experiments. Total RNA obtained from MCV-infected skin tissue was used to confirm these results. Three MCV early transcripts, mc002L, mc004.1L, and mc005L, produced distinct bands on rapid amplification of their 3' ends (3' RACE). The 5' mapping of transcription start sites of MCV open reading frames (ORFs) mc002L, mc004.1L, mc005L, and mc148R revealed that the MCV RNA polymerase transcription start sites are consistently located between 11 and 13 nucleotides downstream of the early MCV consensus promoter signal. When cDNA from both 5' and 3' mapping experiments was analyzed, MCV ORFs mc004. 1L and mc005L were found to be transcribed as a single bicistronic mRNA. The transcript from MCV ORF mc066L, encoding a glutathione peroxidase, was detected in in vitro synthesized MCV mRNA as well as in total RNA from MCV-infected human embryonic fibroblasts and MCV-infected skin. This indicates that despite the lack of an early MCV consensus promoter signal immediately proximal to the start codon, this particular gene is transcribed early during MCV infection.
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PMID:Characterization of early gene transcripts of molluscum contagiosum virus. 1020 26