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:2.7.7.6 (RNA polymerase)
34,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Biological properties of an AIDS agent first isolated from a native citizen in the USSR are presented. The source of the virus was a young Byelorussian woman who in the near past had had sexual contacts with a citizen from one of the Central Africa countries. The isolate is thought to be of HIV-I type. It replicated perfectly in many continuous lymphocyte lines and had HIV-characteristic morphology. The protein spectrum of the isolate was gp120, gp41, p65/51, p55, p32, p24, p17. Reverse transcriptase activity was detected in the culture fluid of the virus-containing cell cultures. The isolate was designated HIV-IZ.
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PMID:[The biological properties of the HIV isolated from a virus carrier living in the Byelorussian SSR]. 214 58

An enzyme immunoassay was developed to detect human immunodeficiency virus type 1 (HIV-1) DNA amplified by polymerase chain reaction (PCR-EIA). A set of primers (outer set) was used in PCR to amplify a segment of the HIV-1 gag gene from peripheral blood mononuclear cells. Hybrids between the amplified DNA and a RNA probe were measured in a microtiter plate immunoassay using a beta-D-galactosidase-conjugated monoclonal antibody to DNA-RNA hybrids and a fluorescent substrate. A second set of primers (nested set) located within the outer set was used in PCR with a known template to prepare the probe. One primer of the nested set included the T7 RNA polymerase promoter at its 5' end allowing transcription of a single-stranded RNA probe. Ten copies of HIV-1 DNA could be detected by PCR-EIA (42 fluorescent units with a background of 18 fluorescent units) compared with a detection limit of 1000 copies by ethidium bromide-stained agarose gel. HIV-1 DNA was detected by PCR-EIA in peripheral blood mononuclear cells from 32 of 33 seropositive patients (range 54-810 fluorescent units), and 0 of 25 seronegative patients (range 20-40 fluorescent units) (sensitivity 97%; specificity 100%). PCR-EIA offers a practical and nonisotopic method to objectively measure PCR-amplified HIV-1 DNA and has the potential for the measurement of other microbial pathogens in human body fluids.
AIDS Res Hum Retroviruses 1990 Jun
PMID:Enzyme immunoassay for detection of hybrids between PCR-amplified HIV-1 DNA and a RNA probe: PCR-EIA. 174 86

Reverse transcriptase activity of the human immunodeficiency virus (HIV) was blocked in vitro by immunoglobulin G (IgG) derived from certain individuals infected with this retrovirus. A heterogeneous immune response for inhibition of enzyme function was noted. Catalytic activity was depressed by 50% or more with the use of 10 micrograms of IgG from 11 of 16 HIV-seropositive asymptomatic carriers, but from 0 of 8 seronegative controls and 2 of 12 patients with acquired immune deficiency syndrome (AIDS) or the AIDS-related complex (ARC). The inhibitor was confined to the F(ab')2 fragment. It was not directed against the poly(rA) X oligo(dT) template, nor against major envelope or structural viral antigens, and did not cross-react with bacterial, avian, or other mammalian DNA polymerases. It did not correlate with recognition of polymerase antigens by radioimmunoprecipitation. Loss of this inhibitor may be associated with development of clinical disease. Ten asymptomatic HIV-seropositive carriers with high titers of IgG antibodies to reverse transcriptase were followed for a mean of 3 years. All of four lost inhibitory capability prior to development of AIDS or ARC, while titers persist in the six who remain clinically healthy.
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PMID:Characterization and clinical association of antibody inhibitory to HIV reverse transcriptase activity. 243 4

In vitro experiments were conducted to assess whether bedbugs (Cimex lectularius and Cimex hemipterus) and mosquitoes (Aedes aegypti formosus) could act as vectors of HIV. These insects engorged through a membrane on a blood-virus mixture. Female bedbugs were larger than males and took larger blood-meals when fed to repletion. It was determined that the full blood-meal of a female bedbug contained 0.09 x 10(5) tissue culture infectious doses (TCID) of virus and a male 0.07 x 10(5) TCID, while partial meals taken when feeding was interrupted contained 0.013 x 10(5) TCID and 0.015 x 10(5) TCID for female and male bugs, respectively. Reverse transcriptase activity was assayed after culture of insect extracts in H9 cells: this showed survival of virus in C. lectularius for up to 4 h, in C. hemipterus for up to 1, possibly 2 h, but no survival in Ae. aegypti formosus. Four attempts to transmit the virus by interrupted feeding by C. lectularius from a blood-virus mixture to uninfected blood failed. It is concluded that Ae. aegypti formosus and probably other mosquitoes are not mechanical vectors of HIV and that such transmission is also unlikely to occur in bedbugs under natural conditions.
AIDS 1987 Sep
PMID:Experimental assessment of bedbugs (Cimex lectularius and Cimex hemipterus) and mosquitoes (Aedes aegypti formosus) as vectors of human immunodeficiency virus. 245 May 52

The human immunodeficiency virus type 1 (HIV-1) shows extensive genetic variation and undergoes rapid evolution. The fidelity of purified HIV-1 reverse transcriptase was measured during DNA polymerization in vitro by means of three different assays. Reverse transcriptase from HIV-1 introduced base-substitution errors in DNA from the bacteriophage phi X174 amber3 at estimated frequencies of 1/2000 to 1/4000. Analyses of misincorporation rates opposite a single template adenine residue showed that HIV-1 reverse transcriptase catalyzed nucleotide mismatches with a specificity of A:C much greater than A:G greater than A:A. The high error rate of HIV-1 reverse transcriptase in vitro translates to approximately five to ten errors per HIV-1 genome per round of replication in vivo. This high error rate suggests that misincorporation by HIV-1 reverse transcriptase is, at least in part, responsible for the hypermutability of the AIDS virus. The specificity of misincorporation may provide a basis for the systematic construction of antiviral nucleosides.
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PMID:Fidelity of HIV-1 reverse transcriptase. 246 Sep 24

Human immunodeficiency virus (HIV) was detected by assay of reverse transcriptase activity in a "virus pellet" obtained by differential sucrose density centrifugation of cell-free semen from three patients with the acquired immune deficiency syndrome (AIDS), one individual with AIDS-related complex (ARC), and in an asymptomatic homosexual male. Reverse transcriptase assays indicated virus concentrations in the range of 10(8) particles/ml of semen, an accumulation substantiated by electron microscopic visualization of cell-free virus. This is the first description of cell-free retrovirus in seminal fluid and at a greater concentration than reported for blood or other body fluids or tissues. These results suggest that the male reproductive tract of humans may be a reservoir of HIV expression, and raises the possibility that the cells lining the epididymal lumen could be chronically infected with HIV. These are important considerations in formulating treatment and preventive strategies.
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PMID:Detection of human immunodeficiency virus in cell-free seminal fluid. 263 53

Reverse transcriptase from the simian immunodeficiency virus (SIV) was found to have kinetic behavior similar to that of enzyme from the human immunodeficiency virus (HIV). Michaelis constants for the substrates TTP and dGTP and inhibition constants for the inhibitors 3'-azido-3'-deoxythymidine 5'-triphosphate, 2',3'-dideoxythymidine 5'-triphosphate, and 2'-3'-dideoxyguanosine 5'-triphosphate were obtained for SIV reverse transcriptase and were found to be similar to the corresponding values for HIV reverse transcriptase. Thus, the interaction of SIV reverse transcriptase with nucleotide analogs appears to be indistinguishable from that of the HIV enzyme, suggesting that SIV/simian acquired immunodeficiency syndrome (SAIDS) is a potentially good model of AIDS.
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PMID:Kinetics and inhibition of reverse transcriptase from human and simian immunodeficiency viruses. 246 88

Carbocylic 2',3'-didehydro-2',3'-dideoxyguanosine (Carbovir; NSC 614846) is an antiretroviral agent which may be useful in the treatment of AIDS. We have synthesized the 5'-triphosphate of Carbovir and examined its ability to inhibit human immunodeficiency virus type 1 (HIV-1) reverse transcriptase (EC 2.7.7.49) and other retroviral reverse transcriptases, as well as human DNA polymerases alpha, beta, gamma (EC 2.7.7.7) and DNA primase (EC 2.7.7.6). Carbovir triphosphate emerges as a highly selective inhibitor of reverse transcriptases with little, if any, effect on the cellular enzymes. 3'-Azido-2',3'-dideoxythymidine (AZT) triphosphate and the two dideoxynucleoside triphosphates, ddTTP and ddGTP, inhibited HIV-1 reverse transcriptase to the same degree as Carbovir triphosphate, but were less selective in that they also inhibited DNA polymerases beta and gamma. We conclude that Carbovir is a highly selective antiretroviral agent.
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PMID:Comparison of the effect of Carbovir, AZT, and dideoxynucleoside triphosphates on the activity of human immunodeficiency virus reverse transcriptase and selected human polymerases. 247 36

The author gives a survey of groups of substances which have a marked and selective effect on HI thus serving as potential chemotherapeutical means against AIDS. They can be divided into three groups: 1. anionic substances, 2. 2, 3-dideoxynucleoside analogues and 3. sulphate polysaccharides. The mechanism of the effect of the substances of the 2nd group probably inhibits reverse HIV transcriptase. The substances of the 3rd group are to prevent adsorption of virus particles by the cells. The substances of the 1st group inhibit HIV transcriptase but also interfere with the adsorption process of the virus particles, or with other stages and phases of the HIV replication cycle. The crystallized substances of these groups should be further studied as potential therapeutic agents for the treatment of AIDS and other retrovirus infections (PMEA, D4T, dextran-sulphate, pentosan, polysulphate and others). The survey also includes information on the so-called anti-sense RNA.
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PMID:[Perspectives in AIDS chemotherapy]. 257 16

The human immunodeficiency virus (HIV-1) envelope gene was expressed in large-scale microcarrier cultures of Vero cells using a system involving coinfection with two recombinant vaccinia viruses. One recombinant contained the bacteriophage T7 RNA polymerase gene under control of a vaccinia virus promoter. The second contained the HIV-1 gp160 gene flanked by T7 promoter and termination sequences. The protein was expressed on the surface of infected cells, and it was shown to have a molecular weight of 160 kD and to react with gp41 and gp120 specific monoclonal antibodies. After purification by successive affinity and ion-exchange chromatography, the protein was demonstrated to be present in a particulate form with a diameter in the range of 15-30 nm. When injected into goats a high-titer gp160 specific antibody response was elicited and group-specific neutralizing activity could be demonstrated in vitro. The immunogenicity of the protein was also studied in conjunction with a number of adjuvant formulations, and the highest potency in mice was obtained using a preparation with 0.2% Al(OH)3 and 0.25% deoxycholate.
AIDS Res Hum Retroviruses 1989 Apr
PMID:Large-scale production and purification of a vaccinia recombinant-derived HIV-1 gp160 and analysis of its immunogenicity. 271 66


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