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:2.7.7.49 (reverse transcriptase)
31,746 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

LLC-MK2 cells chronically infected with two strains of rubella virus, HPV-77 and Thomas, have been examined over several months to find out the mechanism of persistence. Evidence is given for the presence of defective particles in these cultures by finding virion RNA which sedimented at 12S instead of the 40S typical of the fully infectious virus. A 'provirus' DNA copy of the rubella virus genome was not detected by methods which included filter hybridization and in situ hybridization, or by treatment of the chronically infected cells with mitomycin C, antinomycin D or 5-bromodeoxyuridine. In addition, the chronically infected cells contained RNA-dependent RNA polymerase activity, but no RNA-dependent DNA polymerase activity.
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PMID:Mechanism of persistence of rubella virus in LLC-MK2 cells. 11 97

A previous report described a cell isolate presumed to have arisen by accidental cocultivation (contamination) of the Chang 'liver' cell line and rheumatoid synovial cells. This cell isolate had the same glucose-6-phosphate dehydrogenase isoenzyme as the Chang cell and also some shared antigens. It clearly differed in its karyotype, its ability to grow in semisolid agar, and in the possession of bleb-like projections of the cytoplasmic membrane filled with collections of beaded or granular material. In addition, it had a novel antigen(s) not present in the Chang cell. As these properties might have been acquired from the synovial cells and because the bleb structures resembled those seen in some cell lines transformed by leucovirus the cell isolate has been further studied. Cytochemical methods at the light and electron microscope level showed that the granular material was polysaccharide in nature, probably glycogen. No evidence was found of the presence of a virus or a viral genome using a variety of techniques including attempted induction followed by 3H-uridine labelling of the cultures, and assay of the supernatant fluid from the culture for viral RNA-dependent DNA polymerase. In addition, cell extracts were not found to contain viral RNA-dependent DNA polymerase or RNA-dependent RNA polymerase. No rubella virus or leucovirus interspecies antigens were detected on the cell membranes.
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PMID:Cytology of rheumatoid synovial cells in culture. IV. Further investigations of cell lines cocultivated with rheumatoid synovial cells. 18 45

To investigate the etiologic agent associated with Kawasaki disease (KD), we initially established a cocultivation system using concanavalin A (Con A)-stimulated lymphoblastoid cells obtained from each retrovirus-seronegative individual's peripheral blood mononuclear cells (MNCs) cocultivated with each of 1) 40 patients with KD, 2) 10 patients with other viral infection and skin rash, and 3) 10 age- and sex-matched normal controls. Five major findings suggested that virus-like particles with reverse transcriptase (RT) activity are associated with KD. First, RT activity appeared significantly higher on day 12 after the onset of fever in the KD patients than in those with other viral infections and normal controls (dTMP incorporation: 3,645 +/- 248 vs. 434 +/- 50 vs. 412 +/- 46 cpm, P < 0.0001). Second, the RT activity was not endogenous, because the Con A-stimulated lymphoblastoid cells were obtained from the individuals who were negative for retrovirus. Third, virus-like particles (80-100 nm in diameter) by electron microscopy were found in the concentrated pool supernatants of particulate fraction containing RT activity subjected to sucrose density gradient, obtained from KD patients. Fourth, the viral product, a 31.4 kilodalton molecule, was detected by SDS-PAGE after internal labelling (methionine-S35) and density gradient centrifugation. Fifth, using a "retrovirus universal pol gene region" as a primer and the RT-PCR method, a retrovirus-specific band was detected in the cocultivated supernatants obtained from four KD and one AIDS patients but not in patients with rubella or in healthy controls.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Virus-like particles with reverse transcriptase activity associated with Kawasaki disease. 128 52

The biochemical nature of rubella virus and type 2 hybrid virus, which is a recombinant between rubella virus and a latent retrovirus of BHK21 cells, has been characterized. Type 2 hybrid virus carries DNA polymerase able to copy exogenous DNA. However, disrupted type 2 hybrid virions do not synthesize detectable amounts of DNA using the endogenous viral RNA or synthetic poly(rA)/oligo(dT) primed as a template. Thus, the type 2 hybrid virus DNA polymerase has no detectable reverse transcriptase activity. Rubella virus and type 2 hybrid virus RNA can serve as templates for avian myeloblastosis virus (AMV) reverse transcriptase, although they are inefficient. The addition of oligo(dT) to these viral RNA showed no significant stimulation of their template activity for AMV reverse transcriptase. The oligo(dT)-cellulose affinity column bound neither rubella virus nor type 2 hybrid virus RNA. This suggests that both RNA genomes have a very short poly(A) tail at their 3' end. Thus, complementary DNA (cDNA) synthesis by AMV reverse transcriptase using oligo(dT) primers showed no preferential reverse transcription from the genomic 3' terminus and produced only short cDNA fragments (about 200 nucleotides). We cross-hybridized these short cDNA fragments with their viral RNA, assuming that they are copies of random sites of the genome. These cDNA-RNA hybridization analyses of physical homology between type 2 hybrid virus and rubella virus genomes revealed that about 70% of the type 2 hybrid virus genome is derived from about an 85% portion of the rubella virus genome. These values indicate that the size of the type 2 hybrid virus genome is about 21% larger than that of the rubella virus genome. Co-sedimentation studies of these viral RNA by sucrose density gradient centrifugation confirmed that the molecular weight of type 2 hybrid virus RNA is 20% higher than that of rubella virus RNA. We propose a genomic structure of the type 2 hybrid virus taking into account both physical and biochemical data.
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PMID:Hybrids between rubella virus and a latent virus of baby hamster kidney cell line BHK21: characterization of rubella virus and type 2 hybrid virus genomes and determination of their physical homology. 169 23

The sequence of the 1600 3' terminal nucleotides of the RNA of rubella virus was determined from cDNA synthesized from both virion and intracellular RNA using reverse transcriptase and an oligodeoxythymidine primer and cloned into a bacterial plasmid vector. This sequence contained the complete coding sequence for virion envelope protein E1 and a 57 nucleotide nontranslated region between the stop codon for E1 and the poly A tract. The predicted size for E1 was 481 amino acids and within this sequence were three potential N-linked glycosylation sites and a putative trans-membrane domain near the carboxy terminus. Immediately preceding the E1 coding region was a putative signal sequence. No homology was found at either the amino acid or nucleotide level between the region of the rubella virus genome sequenced and corresponding regions of the genomes of the alphaviruses, the other genus of the family Togaviridae for which sequence information has been obtained.
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PMID:Molecular cloning and sequencing of the region of the rubella virus genome coding for glycoprotein E1. 375 48

The identification of endogenous avian leukosis virus (ALV) and endogenous avian retrovirus (EAV) in chick cell-derived measles and mumps vaccines in current use has raised concern about transmission of these retroviruses to vaccine recipients. We used serologic and molecular methods to analyze specimens from 206 recipients of measles, mumps, and rubella (MMR) vaccine for evidence of infection with ALV and EAV. A Western blot assay for detecting antibodies to endogenous ALV was developed and validated. All serum samples were negative for antibodies to endogenous ALV by Western blot analysis. Peripheral blood lymphocyte samples from 100 vaccinees were further tested by polymerase chain reaction for both ALV and EAV proviral sequences; all were negative. Matching serum samples were tested by reverse transcriptase polymerase chain reaction for ALV and EAV RNA, and all 100 samples were negative, providing no evidence of viremia. These findings do not indicate the presence of either ALV or EAV infection in MMR vaccine recipients and provide support for current immunization policies.
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PMID:Lack of evidence of endogenous avian leukosis virus and endogenous avian retrovirus transmission to measles, mumps, and rubella vaccine recipients. 1126 96

Live virus vaccines for human use, 29 monovalent vaccines against measles, mumps, rubella or polio, eight polyvalent vaccines against measles-mumps-rubella and one bacterial polyvalent vaccine against Streptococcus pneumoniae, were tested by reverse transcriptase-nested PCR for the presence of petivirus or pestivirus RNA. Twenty-four samples were selected from European manufacturers, ten were from U.S.A. and four from Japan. Five (13.1%) out of 38 tested samples were positive for pestivirus RNA. Three vaccines (rubella and two measles) were from Europe and two (mumps and rubella) from Japan. The 5'-untranslated genomic region of the contaminant pestivirus RNA were amplified by reverse transcription-PCR and sequenced. Analyses based on primary nucleotide sequence homology and on secondary structures, characteristic to genotypes, revealed that the cDNA sequences belonged to bovine viral diarrhea virus (BVDV). A cDNA sequence, detected from one measles sample, belonged to BVDV-1b genotype. Pestiviral cDNA detected from the Japanese mumps and rubella vaccine samples, belonged to the BVDV genotypes 1a and 1c, respectively. Analysis on two cDNA sequences detected from measles and rubella vaccine samples from Europe showed their appurtenance to a new genotype, BVDV-1d. These findings indicate that contamination by animal pestivirus may occur in biological products for human use.
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PMID:Genotypes of pestivirus RNA detected in live virus vaccines for human use. 1150 99

Mumps has re-emerged as an infection in the developed world. Its epidemiology has changed, with the majority of cases now primarily affecting adolescents and adults. While mumps is easily suspected if parotitis is present, parotitis is absent in 10%-30% of symptomatic cases. Mumps is a systemic infection with a variety of extra-parotid complications. In Australia, mumps diagnosis is confirmed by antibody testing and reverse transcriptase-polymerase chain reaction techniques. Suitable specimens for testing are serum, saliva, urine and cerebrospinal fluid. Treatment is generally supportive, although intravenous immunoglobulin therapy may have a future role in mumps management. Interferon alpha-2b treatment may be considered specifically for mumps epididymo-orchitis. Mumps vaccine is included in the measles-mumps-rubella (MMR) vaccine. In Australia, this vaccine is routinely administered at the ages of 1 and 4 years. Serious reactions to the mumps components of the MMR vaccine are rare.
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PMID:Mumps: a resurgent disease with protean manifestations. 1892 41

Rubella is an acute infectious disease that normally has a mild clinical course. However, infections during pregnancy, especially before week 12 of gestation (WG), can cause severe birth defects known as congenital rubella syndrome (CRS). The aim of this study was to perform genotyping and molecular characterization of rubella viruses involved in congenital infections in France over the past 15 years (1995 to 2009). Amniotic fluid (AF) specimens (n = 80) from pregnant women with congenital rubella infections (CRI) before week 20 of gestation, and a few other samples available from children/newborns with CRS (n = 26), were analyzed. The coding region of the rubella virus E1 gene was amplified directly from clinical specimens by reverse transcriptase PCR, and the resulting DNA fragments were sequenced. Sequences were assigned to genotypes by phylogenetic analysis with rubella virus reference sequences. Sufficient E1 gene sequences were obtained from 56 cases. Phylogenetic analysis of the sequences showed that at least five different genotypes (1E, 1G, 1B, 2B, and 1h) were present in France and were involved in congenital infections, with a strong predominance of genotype 1E (87%). This is one of the very few comprehensive studies of rubella viruses involved in CRI. The results indicated that over the past 15 years, multiple introductions of the dominant genotype E caused most of the CRI cases in France. A few sporadic cases were due to other genotypes (1B, 1G, 1h, 2B).
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PMID:Phylogenetic analysis of rubella viruses involved in congenital rubella infections in France between 1995 and 2009. 2046 61

Rubella virus (RV) usually causes a mild disease. However, infection during the first trimester of pregnancy often leads to severe birth defects known as congenital rubella syndrome (CRS). Although wild-type RVs exist and circulate worldwide, their genotypes remain unknown in many countries. The aim of this study was to identify the molecular characteristics of RVs found in Vietnam during the years 2009-2010 and to provide the first data concerning RV genotypes in this country. Throat swab samples were collected between 2009 and 2010 from four CRS cases and nine rubella infection cases visiting one Children's Hospital and one outpatient clinic in Ho Chi Minh City. The 739-nucleotide coding region of the RV E1 gene recommended by the World Health Organization was amplified by reverse transcriptase PCR, and the resulting DNA fragments were then sequenced. Sequences were assigned to genotypes by phylogenetic analysis with RV reference strains. RV RNA was detected in 11 clinical specimens. Phylogenetic analysis of the sequences showed that all 11 strains belonged to 2B genotype. Several variations in amino acids were found, among which five changes were involved in the B and T cell epitopes. These data indicate that viruses of genotype 2B were circulating in Vietnam. The increasing information about RV genotype in Vietnam should aid in the control of rubella infection and CRS in this country.
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PMID:Phylogenetic analysis of rubella viruses in Vietnam during 2009-2010. 2233 13


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