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)

HIV2 strains were isolated from a Gambian with neuro-AIDS (HIV2D194) and from an asymptomatic Ghanian (HIV2D205). Like HIV1 biological subtype c, both isolates grew slowly and induced few or no syncytia, but eventually produced high levels of particle-associated reverse transcriptase (RT) in cultures of fresh peripheral blood lymphocytes. Each produced even higher levels of RT in fresh human macrophages, especially HIV2D194, where maximal RT values of 1,800,000 cpm/ml supernatant of approximately 30,000 cells were measured. The viruses were molecularly cloned after a single passage in culture. Restriction site analysis showed heterogeneity within each isolate. Nucleotide sequence analysis of HIV2D194 revealed that, genetically, it is a member of the prototypic HIV2 family, displaying 12% divergence vs. HIV2ROD and HIV2NIHZ. In contrast, HIV2D205 is the most highly divergent HIV2 strain yet described: it is equidistant in relation between the known HIV2 strains and the SIVMAC isolates (23-24% nucleotide sequence divergence).
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PMID:Molecular cloning of two west African HIV2 isolates that replicate well in macrophages. 169 22

Two degenerate oligonucleotide primers derived from regions of pol conserved among retroviruses have been synthesized. Polymerase chain reactions utilizing these primers amplify a 135-bp pol fragment in every retrovirus DNA tested to date. The polymerase chain reaction has been linked to a reverse transcriptase step so that a pol-specific DNA fragment can be obtained from a moderate amount of a purified retrovirus or viral RNA. The identity of an unknown retrovirus can be determined by sequencing of the amplified fragment following molecular cloning. This procedure was tested on an unidentified (non-HIV) retrovirus expressed by a B-cell lymphoma line obtained from an AIDS patient. Our PCR assay identified the retrovirus as being highly similar to Mason-Pfizer monkey virus (MPMV) and simian retrovirus 1, which are closely related immunosuppressive type D viruses that cause simian AIDS.
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PMID:The use of primers from highly conserved pol regions to identify uncharacterized retroviruses by the polymerase chain reaction. 169 69

Concentration of monovalent and divalent cations, anionic detergent, reducing agent and nucleotides, as well as pH, temperature, and incubation time were optimized for high levels of HIV-1 endogenous reverse transcriptase activity. In addition, mellitin, a peptide substitute for anionic detergent, and oligo(dT)12-18 were found to stimulate nucleic acid synthesis. This HIV-1 endogenous reaction demonstrated RNA- and DNA-dependent DNA polymerase activities. Nucleic acid intermediates and final products included RNA:DNA hybrids as well as single- and double-stranded DNA. The complementary DNA products formed were representative of all regions of the HIV-1 genome.
AIDS 1990 Mar
PMID:Optimal conditions for synthesizing complementary DNA in the HIV-1 endogenous reverse transcriptase reaction. 169 15

Our recent efforts have been directed at the development of selective inhibitors of different classes of viruses, including adeno, pox, and herpesviruses [herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2), varicella-zoster (VZV), cytomegalovirus (CMV), Epstein-Barr virus (EBV)], (+/-)RNA viruses (reo- and rotavirus), (-)RNA viruses (influenza, parainfluenza, measles, respiratory syncytial, vesicular stomatitis and rabies virus) and retroviruses [i.e. human immunodeficiency virus (HIV), the causative agent of AIDS]. In this search, the following molecular targets were envisaged: for DNA viruses in general, the viral DNA polymerase; for herpes simplex virus and varicella-zoster virus, the viral DNA polymerase via a specific phosphorylation by the viral 2'-deoxythymidine (dThd) kinase; for (+/-)RNA and (-)RNA viruses, S-adenosylhomocysteine (SAH) hydrolase, a key enzyme in transmethylation reactions required for the maturation of viral mRNA; for retroviruses, reverse transcriptase as initiator of virus replication and/or cell transformation; and for several enveloped viruses (i.e. retro-, herpes- and rhabdoviruses), virus adsorption to the outer cell membrane. Several new compounds have been developed that appear to act at these targets: i.e. (E)-5-(2-bromovinyl)-2'-deoxyuridine [bromovinyldeoxyuridine (BVDU)] and derivatives thereof [i.e. carbocyclic BVDU (C-BVDU)] as well as derivatives of acyclovir (i.e. 8-substituted acyclovir derivatives) as inhibitors of herpesviruses; (S)-9-(3-hydroxy-2-phosphonylmethoxypropyl)adenine [(S)-HPMPA], 9-(2-phosphonylmethoxyethyl)adenine (PMEA) and other phosphonylmethoxyalkylpurines and -pyrimidines as inhibitors of DNA viruses and retroviruses; acyclic and carbocyclic analogues of adenosine [such as (S)-9-(2,3-dihydroxypropyl)adenine [S)-DHPA), carbocyclic 3-deazaadenosine (C-c3Ado), (RS)-3-adenin-9-yl-2-hydroxypropanoic acid (AHPA) alkyl esters, neplanocin A, 3-deazaneplanocin A and the 5'-nor derivatives of neplanocin A and 3-deazaneplanocin A] as inhibitors of (+/-)RNA and (-)RNA viruses; 2',3'-dideoxynucleoside analogues as inhibitors of retroviruses; and sulfated polysaccharides (i.e. heparin, dextran sulfate, pentosan polysulfate, mannan sulfate), sulfated polyvinylalcohol and co-polymers of sulfated polyvinylalcohol with acrylic acid as inhibitors of retro-, herpes- and rhabdoviruses.
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PMID:Selective virus inhibitors. 169 49

A better understanding of the structure and biochemical properties of the replicative machinery of human immunodeficiency virus type 1 (HIV-1) may be useful in the screening and design of drugs that could be used to treat AIDS. We have previously described a recombinant strain of Escherichia coli that produces HIV-1 reverse transcriptase (RT). Fermentation conditions for the large-scale growth of the bacterial strain and a protocol for the purification of an enzymatically active 66-Kd form of the RT have been developed. The purified RT has all of the appropriate enzymatic functions and properties. The recombinant protein can be substituted for the viral enzyme in structural and biochemical studies and used in screens for drugs that could inhibit HIV replication.
AIDS Res Hum Retroviruses 1990 Jun
PMID:HIV-1 reverse transcriptase purified from a recombinant strain of Escherichia coli. 169 80

The virion particles of all retroviruses contain reverse transcriptase, a multifunctional enzyme required for the synthesis of a DNA copy of the viral RNA genome soon after entry into the infected cell. The enzyme is the target of the major antiviral drugs currently in use in the treatment of AIDS. This article reviews the strategies used by different retroviruses for the synthesis of the enzyme; the structure of the enzymes encoded by various viruses; the activities inherent in the enzyme; and the application of those activities to the process of reverse transcription of the viral RNA.
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PMID:Retroviral reverse transcriptase: synthesis, structure, and function. 169 94

Direct infection of glia by human immunodeficiency virus type 1 (HIV-1) has been suggested as one of several mechanisms responsible for the severe neurologic complications observed in both neonates and adults with the acquired immunodeficiency syndrome. We have demonstrated by protein immunoblotting analysis that HIV-1 infection of human fetal glial cells isolated from the dorsal root ganglia (DRG) of the developing human peripheral nervous system results in viral gag antigen expression with little, if any, detectable env gene products. No cytopathogenicity was evident in the infected cell population. Blot hybridization analyses indicate transient expression of the HIV-1 genome with maximum levels of virus-specific RNA being observed between 2 and 3 days postinfection and decreasing below the limits of detection by 16 days postinfection. To determine whether infection of the human fetal DRG glial cell population culminates in the production and release of infectious HIV-1, cocultivation and reverse transcriptase assays were performed. Direct assay of HIV-1-infected neural cell supernatants as well as exposure of permissive SupT1 cells to these HIV-1-infected neural cell supernatants resulted in no demonstrable reverse transcriptase activity in either the HIV-1-infected DRG glial cell supernatants or the SupT1 cell supernatants. Although transmission electron microscopy analyses have suggested the absence of intracellular viral particles, highly electron-dense inclusions in the cytoplasm of HIV-1-infected DRG glial cells were observed. The nature of the intracellular cytoplasmic inclusions is under current investigation. Cumulatively, these data suggest that the interaction of HIV-1 with human fetal DRG neural cells results in transient expression of the HIV genome culminating in a nonproductive infection.
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PMID:Analysis of nonproductive human immunodeficiency virus type 1 infection of human fetal dorsal root ganglia glial cells. 169 19

A culture of rhesus monkey peripheral blood lymphocytes was divided into two parts; one was kept as an uninfected control, and the other was infected with a strain of simian immunodeficiency virus (SIVmac251) originally isolated from a rhesus monkey that died of a malignant lymphoma associated with acquired immune deficiency syndrome. Both cultures were sampled at successive intervals from 1 to 40 days postinfection. Each sample was subjected to in situ hybridization for detection of viral mRNA, immunocytochemical detection of viral core protein (p27), reverse transcriptase assay, electron microscopy, and immunophenotypic characterization of infected cells. These techniques were used to define viral growth kinetics of this novel lentivirus in peripheral blood lymphocytes. The first evidence of SIVmac251 replication was obtained by an in situ hybridization signal for viral mRNA at 2 days postinoculation. This was followed by detection of viral p27 core protein by immunocytochemistry on day 4. Reverse transcriptase activity above control values was not detected until day 8. Budding particles were not found in the infected cultures until 14 days postinfection. Results of in situ hybridization, immunocytochemistry, and reverse transcriptase assay indicated that two bursts of viral replication occurred during the course of this study. The first, at 3 weeks postinfection, was due to infection and subsequent depletion of CD4+ lymphocytes, while the second, 3 weeks later, resulted from a cycle of replication in CD8+ lymphocytes and the remaining CD4+ cells, culminating in the death of all cells on day 39 postinoculation.
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PMID:Study of long-term cultures of simian immunodeficiency virus (SIVmac 251)-infected peripheral blood lymphocytes. 169 33

We have studied the action of ascorbate (vitamin C) on human immunodeficiency virus type 1 (HIV-1), the etiological agent clinically associated with AIDS. We report the suppression of virus production and cell fusion in HIV-infected T-lymphocytic cell lines grown in the presence of nontoxic concentrations of ascorbate. In chronically infected cells expressing HIV at peak levels, ascorbate reduced the levels of extracellular reverse transcriptase (RT) activity (by greater than 99%) and of p24 antigen (by 90%) in the culture supernatant. Under similar conditions, no detectable inhibitory effects on cell viability, host metabolic activity, and protein synthesis were observed. In freshly infected CD4+ cells, ascorbate inhibited the formation of giant-cell syncytia (by approximately 93%). Exposure of cell-free virus to ascorbate at 37 degrees C for 1 day had no effect on its RT activity or syncytium-forming ability. Prolonged exposure of virus (37 degrees C for 4 days) in the presence of ascorbate (100-150 micrograms/ml) resulted in the drop by a factor of 3-14 in RT activity as compared to a reduction by a factor of 25-172 in extracellular RT released from chronically infected cells. These results indicate that ascorbate mediates an anti-HIV effect by diminishing viral protein production in infected cells and RT stability in extracellular virions.
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PMID:Suppression of human immunodeficiency virus replication by ascorbate in chronically and acutely infected cells. 169 93

The development of antiretroviral therapy against acquired immunodeficiency syndrome (AIDS) has been an intense research effort since the discovery of the causative agent, human immunodeficiency virus (HIV). A large array of drugs and biologic substances can inhibit HIV replication in vitro. Nucleoside analogs--particularly those belonging to the dideoxynucleoside family--can inhibit reverse transcriptase after anabolic phosphorylation. 3'-Azido-2',3'-dideoxythymidine (AZT) was the first such drug tested in individuals with AIDS, and considerable knowledge of structure-activity relations has emerged for this class of drugs. However, virtually every step in the replication of HIV could serve as a target for a new therapeutic intervention. In the future, non-nucleoside-type drugs will likely become more important in the experimental therapy of AIDS, and antiretroviral therapy will exert major effects against the morbidity and mortality caused by HIV.
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PMID:Molecular targets for AIDS therapy. 169 73


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