Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.7.49 (reverse transcriptase)
 31,746 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

An ultrastructural study was performed on rabbit epithelial RK-13 cells and CD4+ human T lymphocyte lines infected with various recombinant vaccinia viruses (RVVs) expressing genes of human immunodeficiency virus (HIV): the mature p17 or p24 gag domain alone, the entire or truncated gag gene, the reverse transcriptase domain, or the gag-pol genes with a frameshift mutation. Cells infected with RVVs that produced the gag polyprotein with a predicted Mr of more than 48K showed budding and release of HIV-like particles into the extracellular space. These particles were not observed in cells expressing a truncated gag gene (p17 and p24 regions). Mature HIV-like particles were observed extracellularly when the entire gag gene and the protease region of the pol gene were expressed. In contrast, in cells infected with RVVs that contained the gag-pol gene with a frameshift mutation, neither recognizable budding structures nor extracellular HIV-like particles could be detected. These results suggest that the gag gene, particularly its 3' terminus, is necessary for the assembly of HIV particles. In addition, the protease region of the pol gene seems to be required for morphological maturation of HIV particles, but complete proteolytic cleavage of the gag protein may prevent bud formation.
J Gen Virol 1991 Oct
PMID:Role of the gag and pol genes of human immunodeficiency virus in the morphogenesis and maturation of retrovirus-like particles expressed by recombinant vaccinia virus: an ultrastructural study. 191 28

An antiviral effect of prostaglandins (PGs) of the A series on the replication of human immunodeficiency virus (HIV) has been determined. In the T cell line C8166 under single growth cycle conditions, PGA1 reduced the number of infectious progeny 1000-fold in the absence of cytotoxicity. Thus, inhibition of HIV replication by PGA1 represents a true antiviral phenomenon. The number and size of virus-induced syncytia, and the amount of viral antigen were also drastically reduced. The effect was specific for PGAs because PGA2 was also inhibitory, whereas PGB1, PGE1 and PGE2 were inactive. Virus adsorption and penetration do not appear to be targets of antiviral action because PGA1 substantially reduced virus replication, even when added 5 h post-infection. PGA1 did not inhibit viral reverse transcriptase, as determined by in vitro assays, suggesting that its antiviral action is not the consequence of a direct inhibitory effect on this enzyme. PGA1 also inhibited the replication of HIV-1 in CEM x 174 cells, but with less potency. Previously, intravenous infusion of PGA1 into human volunteers has shown no significant deleterious side-effects and thus these observations suggest that PGAs might have potential as antiviral agents in humans.
J Gen Virol 1991 Nov
PMID:Prostaglandin A inhibits replication of human immunodeficiency virus during acute infection. 194 Aug 69

Hepatitis B virus (HBV) is the causative agent of hepatocellular carcinoma (HCC) in man. The HBV genome is a circular partially double-stranded DNA molecule of about 3.2 kb. The HBV genome contains four structural genes coding for the HBV envelope (HBsAg) and core (HBcAg/HBeAg) proteins, endogenous DNA-polymerase with the additional enzymatic activity of a reverse transcriptase and polypeptide X functioning as a trans-activator of cellular and viral genes. HBV DNA integration in the genomes of HCCs and hepatocytes of HBV carriers is an important evidence establishing a relationship between the HBV infection and the development of HCC. The mechanism of HBV DNA integration into the cellular genome and the possible role of integrated HBV DNA sequences in the malignant transformation of hepatocytes are discussed.
Mol Gen Mikrobiol Virusol 1990 Feb
PMID:[Human hepatitis B virus and hepatocellular carcinoma]. 215 10

Yeast cells Saccharomyces cerevisiae were transformed by the recombinant plasmids containing the Yeast retrotransposon Ty and the Drosophila mobile element gypsy under the control of a strong Yeast promoter. The exogenous Ty-element induces the complete cycle of Ty-retrotransposition including the TyRNA synthesis, formation of virus-like particles, synthesis of all reverse transcriptase intermediates in the virus-like particles with the subsequent circles formation and transposition. The Drosophila mobile element gypsy is capable of inducing the formation of the virus-like particles containing RNA, DNA and proteins of the Ty-retrotransposon only. The Ty-circles and induction of transposition were not observed. The obtained data demonstrates the existence of the multistep repression system for Ty-transposition cycle. The possibility and efficiency of using the model to study the mechanism for retrotransposon transposition is discussed.
Mol Gen Mikrobiol Virusol 1990 Jul
PMID:[Expression of homologous and heterologous retrotransposons in a model system of yeast cells]. 217 Aug 33

Discontinuous DNA complementary to Escherichia coli 16S + 23S ribosomal RNA was synthesized by random oligonucleotide priming using reverse transcriptase. cDNA generated from native or denatured rRNA template was labelled by incorporation of either [alpha-32P]dCTP or digoxigenin-labelled dUTP during synthesis, followed by template hydrolysis. The specific activity of the radiolabelled cDNA was 10(7)-10(8) c.p.m. (micrograms rRNA template)-1 with 60-92% incorporation after 5 h. The length of the reverse transcript was between 20 and 1140 nucleotides and was unaffected by exclusion of primer. The cDNA probe could detect 3 pg rRNA by quantitative slot blot. In the non-radiolabelling digoxigenin system 3 micrograms template gave 0.5-2.0 micrograms cDNA after 24 h with a length of between 100 and 1225 bases. This probe could detect 50 pg rRNA. Probes were evaluated in the comparison of Pasteurella haemolytica biotypes by hybridization to Southern blots of restriction-endonuclease-digested total DNA. The digoxigenin-labelled probe was used to identify clinical isolates of Campylobacter jejuni to demonstrate its potential use in laboratories requiring high-sensitivity detection without the use of radioisotopes.
J Gen Microbiol 1990 Aug
PMID:Characterization of an rRNA gene-specific cDNA probe: applications in bacterial identification. 226 95

Twelve long-term cell lines were established from peripheral blood mononuclear cells (PBMC) or cerebrospinal fluid cells of patients with human T lymphotropic virus type I (HTLV-1) seropositive tropical spastic paraparesis (TSP) originating from the French West Indies, French Guyana or the Central African Republic. Most of these long-term interleukin-2-dependent cell lines exhibited a pattern characteristic of CD4(+)-activated T cells with high expression of CD2, CD3 and CD4 antigens, associated with a strong density of TAC and DR molecules. Nevertheless, in five cases CD8 expression was present at a significant level. HTLV-I antigens were never detected in uncultured PBMC, but they were expressed in a few cells after short-term culture and after 4 months the majority of the cells were HTLV-I positive, as demonstrated by indirect immunofluorescence (IF) using polyclonal or monoclonal anti-p19 and anti-p24 antibodies. Low and variable levels of reverse transcriptase activity were detected in supernatant fluids of these cell lines only after 4 months of culture, when at least 50% of the cells exhibited HTLV-I antigens by IF. However, numerous type C HTLV-I-like viral particles were detected, mostly in the extracellular spaces, with rare budding particles. Similar findings were found in three T cell lines derived from West Indian and African patients with adult T-cell leukaemia/lymphoma (ATLL). Differences in high Mr polypeptides were detected by Western blot in cell lysates when comparing TSP- or ATLL-derived T cell lines. Thus a signal of 62K was easily detectable in all the TSP lines, but not in the ATLL lines. In all cell lines bands corresponding to p53, p24 and p19 viral core polypeptides were present, as was the env gene-coded protein p46.
J Gen Virol 1990 Feb
PMID:Cell surface phenotype and human T lymphotropic virus type 1 antigen expression in 12 T cell lines derived from peripheral blood and cerebrospinal fluid of West Indian, Guyanese and African patients with tropical spastic paraparesis. 230 64

A serum sample from a patient with hepatitis and samples from two experimentally infected chimpanzees, all with a high infectivity for non-A, non-B hepatitis, were tested for reverse transcriptase. Biopsy confirmed that the hepatocytes of the chimpanzees that received these sera contained the characteristic tubular structures associated with non-A, non-B hepatitis. None of these three sera revealed detectable enzyme activity. We have not been able to confirm the association of reverse transcriptase activity with non-A, non-B hepatitis reported recently.
J Gen Virol 1986 Apr
PMID:Lack of detectable reverse transcriptase activity in human and chimpanzee sera with a high infectivity for non-A, non-B hepatitis. 242 Sep 26

The RNA-dependent DNA polymerase (RDDP) of human immunodeficiency virus (HIV) was purified from sucrose density gradient-banded virus by four successive procedures: anion exchange chromatography, cation exchange chromatography, affinity chromatography on oligo(dT)-cellulose and adsorption chromatography on hydroxyapatite. The enzyme preparation was free of cellular DNA-dependent DNA polymerase activity. The properties of HIV RDDP were determined with a variety of template-primers. Generally, the enzyme used Mg2+ for optimal activity except with (Cm)n X (dG)12-18 as template-primer. Kinetic data (Michaelis constant, Hill coefficient) were calculated for several substrates.
J Gen Virol 1986 Dec
PMID:Functional purification and enzymic characterization of the RNA-dependent DNA polymerase of human immunodeficiency virus. 243 65

Using the calcium-phosphate procedure the plasmid cDm2055, which carries the copia transposable element of Drosophila melanogaster, was co-transfected with the Neor-carrying plasmid pSVCneo-1 into the D. hydei cell line KUN-DH-33 which was free of copia. The Neor transfectants stably carried both plasmids as tandem oligomers integrated in the chromosome and virus-like particles (VLP) were produced specifically in the transfectants that received the copia plasmid. The particles were quite similar in various aspects such as size, morphology, density, RNA content and molecular weight of the major protein component, to retrovirus-like particles (RVLP) that spontaneously appear in cultured cells of D. melanogaster: the reverse transcriptase activity however seemed to be low compared to that of the D. melanogaster RVLP. This finding demonstrates that the retrovirus-like particles (RVLP) in Drosophila cultured cells are produced by the transposable genetic element copia resident in the host chromosomes.
Mol Gen Genet 1987 Apr
PMID:Production of virus-like particles by the transposable genetic element, copia, of Drosophila melanogaster. 243 82

Ninety analogues of suramin have been examined for their ability to inhibit the exogenous reverse transcriptase (RT) of human immunodeficiency virus type I (HIV-I). Of these compounds, 57 inhibited the poly(rC).oligo(dG)-dependent RT activity. Three classes of dose-response curves could be discriminated. Allocation of a compound to one class did not correspond with obvious structural features. Twenty-four substances were superior to suramin in our RT inhibition assay. The RT-inhibitory activity of these compounds did not correlate with their effect against filariae or trypanosomes. Preliminary antiviral evaluation in susceptible human T cells inoculated with HIV-I demonstrated in vitro therapeutic efficacy for some compounds with lower drug-related cellular toxicity than suramin. Certain structural features relevant for the RT-inhibitory effect of these compounds were recognized. Predictions are made for the design of more effective RT inhibitors. Such compounds will help to understand the molecular mechanism of reverse transcription and might be useful in the therapy of retroviral infections.
J Gen Virol 1987 Aug
PMID:Inhibition of human immunodeficiency virus type I reverse transcriptase by suramin-related compounds. 244 Sep 83


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>