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)

Rous sarcoma virus protein p10 is a gag component of the virion present in stoichiometric amount but of unknown function. To characterize this protein, a series of mutants of p10 with linker insertions or deletions was generated by site-directed mutagenesis of a cloned proviral DNA. The deletions and two of the linkers insertions, which disrupted proline pairs, reduced the yield of virus particles upon transfection. These two linker insertion mutants were moreover thermosensitive for this phenotype, producing fewer virus particles at 41 degrees C than at 36 degrees C. Examination of the intracellular viral proteins demonstrated that for all mutants, the amount of gag precursor was similar to the wild-type level. Moreover, the amount of mature gag CA that could be detected by this analysis was similar between each of the mutants and the wild type. This finding suggests that the transport of gag to the membrane and the initial stages of maturation were not affected by the mutations. The virus particles contained normal amounts of active reverse transcriptase, showing that the gag-pol polyprotein was incorporated and cleaved properly. Viral RNA was quantitatively and qualitatively similar in mutant and wild-type virions. However, the infectivity of the mutants virions differed; one of the thermosensitive linker insertions that had no effect on particle production at 36 degrees C was nevertheless noninfectious at that temperature. Together, these data suggest that the p10 protein is involved in a late steps of virus maturation, possibly budding, and perhaps also in an early event of viral infection.
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PMID:Analysis of deletions and thermosensitive mutations in Rous sarcoma virus gag protein p10. 768

We have examined components of the preintegration complex of human immunodeficiency virus type 1 (HIV-1) and have analyzed features which govern the association of these components. HIV-1 nucleoprotein complexes, isolated from nuclear and cytoplasmic extracts of CD4+ cells after acute virus infection, contained viral RNA and DNA in association with viral matrix (MA), integrase (IN), and reverse transcriptase (RT) antigens but not capsid (CA) antigens and possessed integration activity in vitro. Association of IN but not RT or MA antigens with viral DNA was detergent-stable. Analysis of viral DNA synthesis and nuclear import of viral nucleoprotein complexes in the presence of a reversible RT inhibitor demonstrated that reverse transcription of viral RNA could be completed entirely in the host cell nucleus. Our studies demonstrate structural and functional features of the nucleoprotein (preintegration) complex of HIV-1 which are pertinent to the understanding of early events in the lentiviral life cycle.
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PMID:Association of integrase, matrix, and reverse transcriptase antigens of human immunodeficiency virus type 1 with viral nucleic acids following acute infection. 768 60

Rhesus monkeys were dosed orally with 10 mg/kg 5-chloro-3-phenylthioindole-2-carboxamide (L-734,005), a nonnucleoside human immunodeficiency virus type 1 (HIV-1) reverse transcriptase inhibitor, in polyethylene glycol 300. Plasma samples from these monkeys demonstrated greater bioactivity in an HIV-1 reverse transcriptase inhibition assay than anticipated from the parent compound concentrations as determined by an HPLC-UV assay. One major and three minor metabolites, as well as the parent compound, were detected in the plasma. One of the minor metabolites was determined to be several-fold more active, and the major metabolite one-half as active as the parent compound in the inhibition assay. Identical metabolites were formed during an incubation of L-734,005 with rat liver microsomes. The most active minor metabolite was identified as a sulfone analog (L-737,126) of the parent compound by NMR and MS analyses. The less active major metabolite and two relatively inactive minor metabolites were similarly identified as the sulfoxide, 4-hydroxythiophenyl and 6-hydroxyindole analogs of L-734,005. The synthetic sulfone analog was highly potent against HIV-1, with a 95% inhibitory concentration of 3.0 nM for the spread of virus infection in a cell culture.
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PMID:Biotransformation of 5-chloro-3-phenylthioindole-2-carboxamide (L-734,005) in rhesus monkeys and rat liver microsomes to a potent HIV-1 reverse transcriptase inhibitor. 769 Jun 97

Human immunodeficiency virus (HIV) resistance to the nonnucleoside reverse transcriptase inhibitors emerges very rapidly under selection in culture and in patients. In contrast, zidovudine (3'-azido-3'-deoxythymidine [AZT])-resistant HIV generally emerges in patients only after more-prolonged therapy. Although HIV can be cultured from many patients shortly after the initiation of AZT treatment, characterization of the virus that is cultured generally indicates that it is sensitive to AZT. To initiate an evaluation of the mechanisms contributing to early HIV breakthrough in the presence of AZT and other nucleoside analogs, we have utilized replication-defective HIV encoding reporter genes. These recombinant HIV allow a quantitative analysis of a single cycle of infection. Results with these defective HIV indicate that early infection in the presence of AZT often results from the infection of a cell which is refractory to the antiretroviral effects of AZT. Characterization of a cell line derived from one such cell has demonstrated decreased accumulation of AZT triphosphate, increased phosphorylation of thymidine to thymidine triphosphate, and increased levels of thymidine kinase activity. In addition, AZT inhibition of replication-competent HIV infection is also significantly impaired in this cell line. Attempts to detect and characterize the mechanisms responsible for early viral infection after initiation of AZT therapy may result in the development of new strategies for prolonged suppression of viral infection prior to the emergence of drug-resistant virus.
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PMID:Sanctuary growth of human immunodeficiency virus in the presence of 3'-azido-3'-deoxythymidine. 785 95

We report the results of a longitudinal study of RNA splicing patterns in 31 early-stage human immunodeficiency virus disease patients with an average follow-up time of 3 years. Eighteen patients showed no evidence for disease progression, whereas 13 patients either showed a > or = 50% reduction in baseline CD4 count or developed opportunistic infections. Levels of unspliced, tat, rev, and nef mRNAs in peripheral blood mononuclear cells were measured by a reverse transcriptase-quantitative, competitive PCR assay. Viral RNA was detected in all patients at all time points. All 13 rapid progressors had viral RNA loads that were > or = 1 log unit greater than those of the slow progressors. In addition, seven of the rapid progressors showed a reduction of more than threefold in the ratio of spliced to unspliced RNA over the 3 years of follow-up. Conversely, two slow progressors with intermediate levels of viral RNA showed no splicing shift. These results confirm earlier observations that viral RNA is uniformly expressed in early-stage patients. We further show that cellular RNA viral load is predictive of disease progression. Importantly, the shift from a predominately spliced or regulatory viral mRNA pattern to a predominately unspliced pattern both is associated with disease progression and adds predictive utility to measurement of either RNA class alone.
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PMID:Human immunodeficiency virus type 1 cellular RNA load and splicing patterns predict disease progression in a longitudinally studied cohort. 785 28

The majority of causative strains of hemorrhagic fever with renal syndrome (HFRS) are known as Hantaan and Seoul viruses in Korea. The clinical manifestations may be indistinguishable between both viruses, although the clinical course of Hantaan virus infection is more severe than that of the Seoul virus. Therefore, the differentiation of Hantaan or Seoul virus may be important for predicting the prognosis. The primers were selected from the published sequences of the S segments of Hantaan virus strain 76-118 and Seoul virus strain SR-11, which made it possible to obtain the same size of 403 bp amplified product by reverse transcriptase polymerase chain reaction (RT-PCR) and nested PCR from both viral strains. The differentiation of the amplified products was carried out by restriction enzyme digestion. With HindIII, the 403 bp amplified product from Hantaan virus strain 76-118 was cleaved into two segments of 175 bp and 228 bp. By contrast, the 403 bp product from Seoul virus strain SR-11 was not cut by HindIII. With HinfI, the 403 bp amplified product from Hantaan virus strain 76-118 was divided into two bands of 280 bp and 60 bp on the electrophoresis. In the case of the digestion of 403 bp PCR product from Seoul virus strain SR-11 with HinfI, more than four bands (155 bp, 115 bp, 60 bp, and 32/29 bp) were observed on the 2% agarose gel electrophoresis. This rapid technique may be useful for the differential diagnosis of Asian HFRS in Korea.
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PMID:Rapid differentiation between Hantaan and Seoul viruses by polymerase chain reaction and restriction enzyme analysis. 793 Nov 85

Hepatitis C virus (HCV) infection is common in hemodialysis patients, as determined by antibody assays and qualitative polymerase chain reaction (PCR) analysis of serum HCV RNA. To further characterize HCV infection in this population, we measured the viral load in infected hemodialysis patients by a quantitative, competitive PCR assay (QC-PCR) for HCV RNA. Hepatitis C virus RNA levels were correlated with serologic, biochemical, and demographic features of a cohort of hemodialysis patients. Sera from 208 hemodialysis patients were screened for HCV RNA (5' conserved region) by reverse transcriptase PCR (RT-PCR) and HCV-specific antibody. Forty-four patients were antibody positive (21%); among these patients, 34 (77%) were HCV RNA positive. No viremic, seronegative patients were identified. Hepatitis C virus RNA levels quantitated by QC-PCR ranged from 3 x 10(5) to 10(8) molecules of HCV RNA/mL. Male patients had significantly higher mean and median HCV RNA levels (10(7) molecules/mL) compared with female patients (3.6 x 10(6) molecules/mL and 3 x 10(6) molecules/mL, respectfully; P = 0.02). No other demographic or clinical feature of this cohort correlated with HCV RNA levels. Intravenous drug abuse was the most frequently identified risk factor (29% of seropositive patients) for infection with HCV in this population. No association between HCV RNA levels and hepatic enzyme levels (alanine aminotransferase, aspartate aminotransferase, gamma-glutamyl transferase, alkaline phosphatase) was apparent. Hepatitis C virus infection is highly prevalent in our hemodialysis population, and hemodialysis patients, particularly males, have high levels of HCV in serum.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Quantitation of hepatitis C viral RNA in sera of hemodialysis patients: gender-related differences in viral load. 797 21

Enteroviruses are potential etiologic agents of myocarditis and dilated cardiomyopathy (DCM). A recently developed molecular approach has offered evidence of viral infection by detecting the virus genome. The nested reverse transcriptase polymerase chain reaction (nRT-PCR) was used to detect enteroviral RNA in endomyocardial biopsy tissues of myocarditis and DCM. The authors examined 44 tissues obtained from 36 patients with myocarditis, as well as from 10 patients with non-infectious cardiac diseases as controls. Enteroviral RNA was detected in 12 of 36 patients with myocarditis. The second endomyocardial biopsy was carried out in five of the patients, in whom enteroviral RNA was detected at the first biopsy, at intervals from 3 weeks to 8 years after the first biopsy, and enteroviral RNA was found in four and had disappeared in one. In one of the four positive patients at the second biopsy, a third biopsy was carried out 5 months later (6 months after the first), and the RNA was detected. Active myocarditis became clinically and microscopically mild at the second and third biopsies. In one patient who developed DCM, enteroviral RNA was also detected at a second biopsy performed 8 years after the first. Enteroviral infection is a probable cause of myocarditis and enterovirus-infected myocarditis may progress to DCM.
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PMID:Enteroviral RNA in endomyocardial biopsy tissues of myocarditis and dilated cardiomyopathy. 804 3

The purpose of this study was to determine if the myopathy that commonly occurs in patients with AIDS is associated with active HIV-1 infection in the muscle tissues. Seven muscle biopsies from patients infected by HIV-1 and six controls were tested for HIV-1 DNA and RNA using polymerase chain reaction in situ hybridization and reverse transcriptase in situ polymerase chain reaction. HIV-1 DNA was detected in rare cells in only one case by standard in situ hybridization. However, after polymerase chain reaction amplification HIV-1 DNA was detected in many cells in four of seven muscle tissues from patients with the viral infection and in none of the controls. The number of cells with detectable provirus in the tissue positive by standard in situ hybridization increased up to 100-fold after amplification. Most of the HIV-1 infected cells were macrophages, as determined by colabeling experiments that were localized mainly in the areas of myocyte necrosis. Myocyte nuclei that contained amplified HIV-1 nucleic acids were also noted. Most virally infected cells contained HIV-1 transcripts, which is consistent with activated infection. The demonstration of many HIV-1 infected macrophages and myocytes in muscle biopsies from HIV-1 infected patients with myopathy suggests that active viral infection may play a role in the clinical disease state.
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PMID:In situ detection of polymerase chain reaction-amplified HIV-1 nucleic acids in skeletal muscle in patients with myopathy. 805 10

To investigate mother-to-infant transmission of hepatitis C virus, serial follow-up of anti-HCV and hepatitis C virus RNA was undertaken in 11 infants born to hepatitis C virus-infected mothers who had been screened from 11,688 pregnant women. None of the hepatitis C virus-infected mothers was infected by human immunodeficiency virus. Anti-HCV was checked by the second-generation enzyme immunoassay kit, and hepatitis C virus RNA was examined by reverse transcriptase-nested polymerase chain reaction. Hepatitis C virus RNA was found in more than two serum samples in two of these 11 infants; those two infants were regarded as hepatitis C virus-infected. One of the two had hepatitis C virus RNA at the age of 1, 3, and 6 months, but not later. The course of hepatitis C virus RNA and anti-HCV in this baby may reflect fluctuating viral replication in chronic infectious disease or viral clearance in acute infection. The other infant had hepatitis C virus RNA detectable at the age of 3 months and at 15, 18 and 24 months. In the other nine non-hepatitis C virus-infected infants, maternally acquired anti-HCV gradually disappeared by the age of 6 months. The liver function profile fell to the normal range in all the infants, including the two hepatitis C virus-infected infants. This may indicate the subclinical nature of hepatitis C virus infection in infancy. Seven fathers and four siblings of these 11 infants were checked for anti-HCV and liver function tests; none had evidence of hepatitis C virus infection.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Temporal profile of hepatitis C virus antibody and genome in infants born to mothers infected with hepatitis C virus but without human immunodeficiency virus coinfection. 807 41


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