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)

DNA sequencing of the subgroup F human adenovirus serotype 41 (TAK, Ad41) fiber gene revealed the presence of two adjacent open reading frames encoding information for proteins with molecular weights of 60.6 kDa and 41.4 kDa (Pieniazek, et al; Nucleic Acids Res. 18: p. 1901, 1990). In this paper, various approaches were used to characterize the two proteins and determine whether both fibers were expressed in infected cells as well as on viral particles. We initially used a reverse transcriptase-polymerase chain reaction with primers for the short and long fiber genes to amplify mRNA from Ad41 infected HEp-2 cells at 48 h post-infection. Two distinct DNA bands; one slightly larger than 1.1 kbp and the other at about 1.7 kbp were identified. Second, we used polyclonal anti-Ad41 virion and monoclonal anti-Ad5 fiber antibodies to demonstrate that at both 24 and 36 h post-infection, Ad41 expressed two fiber proteins of the expected size. Specifically, by SDS-PAGE, one fiber (short) had a molecular weight of 40 kDa, while the other (long) had a molecular weight of 60 kDa. Third, by electron microscopy, two sizes of fibers were released from CsCl purified virions, both having a characteristic adenovirus morphology, with a knob at one end. The long fiber measured 315A in length and the short fiber was 250A long. These measurements are consistent with the two Ad41 fibers being encoded by the above open reading frames. We also performed a computer search to compare fiber sequences from other human adenovirus serotypes with that of the Ad41 short and long fiber proteins. The primary structure of both Ad41 fibers were found to be similar in that they contained tail, shaft and knob regions. Further, the tail region of both fibers (amino acids 1-42) showed a 74% overall homology to each other and contained the Ad conserved sequence NH2-F-N-P-V-Y-P-Y-COOH. An interesting difference, however, was observed in the shaft region where the long fiber (amino acids 43-389) had twenty-two 16-amino acid repeat motifs, while the short fiber (amino acids 43-233) had only twelve. Finally, we noted that the long fiber knob region was about 15% longer than that of the short fiber, and showed little overall homology. In conclusion, human adenovirus subgroup F (type 41) virions appear to differ from those of all other human adenoviruses (subgenera A-E) in that they contain two fiber genes and correspondingly, two different sized fibers.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Human adenovirus type 41 contains two fibers. 797 82

Virtually all the compounds that are currently used, or under advanced clinical trial, for the treatment of HIV infections, belong to one of the following classes: (i) nucleoside/nucleotide reverse transcriptase inhibitors (NRTIs), (ii) non-nucleoside reverse transcriptase inhibitors (NNRTIs) and (iii) protease inhibitors (PIs). In addition to the reverse transcriptase and protease step, various other events in the HIV replicative cycle are potential targets for chemotherapeutic intervention: (i) viral adsorption, through binding to the viral envelope glycoprotein gp120 (polysulphates, polysulphonates, polyoxometalates, zintevir, negatively charged albumins); (ii) viral entry, through blockade of the viral coreceptors CXCR4 and CCR5 [bicyclams (AMD3100), polyphemusins (T22), TAK-779]; (iii) virus-cell fusion, through binding to the viral glycoprotein gp41 [T-20 (DP-178), siamycins, betulinic acid derivatives]; (iv) viral assembly and disassembly, through NCp7 zinc finger-targeted agents [2,2'-dithiobisbenzamides (DIBAs), azadicarbonamide (ADA)]; (v) proviral DNA integration, through integrase inhibitors such as L-chicoric acid; (vi) viral mRNA transcription, through inhibitors of the transcription (transactivation) process (peptoid CGP64222, fluoroquinolone K-12, Streptomyces product EM2487). Also, in recent years new NRTIs, NNRTIs and PIs have been developed that possess, respectively, improved metabolic characteristics (i.e. phosphoramidate and cyclosaligenyl pronucleotides of d4T), or increased activity against NNRTI-resistant HIV strains, or, in the case of PIs, a different, non-peptidic scaffold. Given the multitude of molecular targets with which anti-HIV agents can interact, one should be cautious in extrapolating from cell-free enzymatic assays to the mode of action of these agents in intact cells. A number of compounds (i.e. zintevir and L-chicoric acid, on the one hand; and CGP64222 on the other hand) have recently been found to interact with virus-cell binding and viral entry in contrast to their proposed modes of action targeted at the integrase and transactivation process, respectively.
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PMID:Novel compounds in preclinical/early clinical development for the treatment of HIV infections. 1089 72

We have demonstrated previously that endothelin-1 (ET-1) mRNA expression is increased in hypertensive rats. The aim of the study reported here was to elucidate the effects of the endothelin (ET) receptor antagonist on the hemodynamic and biochemical parameters in stroke-prone spontaneously hypertensive rats (SHRSPs/Izm). The endothelin-A- and -B- (ETA/ETB) receptor antagonist (TAK-044, Takeda Chemical Industries, Osaka, Japan) was administered subcutaneously at a dose of 10 mg/kg/day from the age of 8 weeks for 4 weeks. Blood samples and tissues of the kidney, heart and brain were obtained at the age of 12 weeks. Tissue expression of ET-1 mRNA was determined by reverse transcriptase-polymerase chain reaction (RT-PCR) followed by Southern blot analysis. Treatment with TAK-044 resulted in a significant decrease in systolic blood pressure (SBP), blood urea nitrogen (BUN), serum creatinine concentration, plasma aldosterone level, heart weight, and kidney weight. In addition, ET-1 contents and mRNA expression level in the kidney, heart and brain were significantly decreased by the treatment with TAK-044. These results suggest that the ET receptor antagonist TAK-044 is able to attenuate ET-1 gene expression in addition to its specific antagonism of the biological actions of ET via the receptors.
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PMID:Hemodynamic and biochemical effects of endothelin-A- and -B-receptor antagonist TAK-044 in stroke-prone spontaneously hypertensive rats. 1107 13

Virtually all the compounds that are currently used, or under advanced clinical trial, for the treatment of HIV infections, belong to one of the following classes: (i) nucleoside/nucleotide reverse transcriptase inhibitors (NRTIs): i.e., zidovudine (AZT), didanosine (ddI), zalcitabine (ddC), stavudine (d4T), lamivudine (3TC), abacavir (ABC), emtricitabine [(-)FTC], tenofovir (PMPA) disoproxil fumarate; (ii) non-nucleoside reverse transcriptase inhibitors (NNRTIs): i.e., nevirapine, delavirdine, efavirenz, emivirine (MKC-442); and (iii) protease inhibitors (PIs): i.e., saquinavir, ritonavir, indinavir, nelfinavir, amprenavir, and lopinavir. In addition to the reverse transcriptase and protease step, various other events in the HIV replicative cycle are potential targets for chemotherapeutic intervention: (i) viral adsorption, through binding to the viral envelope glycoprotein gp120 (polysulfates, polysulfonates, polyoxometalates, zintevir, negatively charged albumins, cosalane analogues); (ii) viral entry, through blockade of the viral coreceptors CXCR4 and CCR5 [bicyclams (i.e. AMD3100), polyphemusins (T22), TAK-779, MIP-1 alpha LD78 beta isoform]; (iii) virus-cell fusion, through binding to the viral glycoprotein gp41 [T-20 (DP-178), T-1249 (DP-107), siamycins, betulinic acid derivatives]; (iv) viral assembly and disassembly, through NCp7 zinc finger-targeted agents [2,2'-dithiobisbenzamides (DIBAs), azadicarbonamide (ADA) and NCp7 peptide mimics]; (v) proviral DNA integration, through integrase inhibitors such as L-chicoric acid and diketo acids (i.e. L-731,988); (vi) viral mRNA transcription, through inhibitors of the transcription (transactivation) process (fluoroquinolone K-12, Streptomyces product EM2487, temacrazine, CGP64222). Also, in recent years new NRTIs, NNRTIs and PIs have been developed that possess respectively improved metabolic characteristics (i.e. phosphoramidate and cyclosaligenyl pronucleotides of d4T), or increased activity against NNRTI-resistant HIV strains [second generation NNRTIs, such as capravirine and the novel quinoxaline, quinazolinone, phenylethylthiazolylthiourea (PETT) and emivirine (MKC-442) analogues], or, as in the case of PIs, a different, non-peptidic scaffold [i.e. cyclic urea (DMP 450), 4-hydroxy-2-pyrone (tipranavir)]. Given the multitude of molecular targets with which anti-HIV agents can interact, one should be cautious in extrapolating from cell-free enzymatic assays to the mode of action of these agents in intact cells. A number of compounds (i.e. zintevir and L-chicoric acid, on the one hand; and CGP64222 on the other hand) have recently been found to interact with virus-cell binding and viral entry in contrast to their proposed modes of action targeted at the integrase and transactivation process, respectively.
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PMID:New developments in anti-HIV chemotherapy. 1156 82

The chemokine receptors CXCR4 and CCR5 are used as co-receptors by the T cell-tropic (X4) and macrophage-tropic (R5) HIV-1 strains, respectively, for entering their host cells. Viral entry can be inhibited by the natural ligands for CXCR4, the CXC chemokine SDF-1 and CCR5, the CC chemokines RANTES, MIP-1alpha and MIP-1beta. Several peptidic compounds, T22 (an 18-mer), T134 (a 14-mer), ALX40-4C (a 9-mer) and CGP 64222 (also a 9-mer), have been identified as CXCR4 antagonists and show anti-HIV activity. Also, the HIV-1 tat protein has been described as a 'natural' CXCR4 antagonist with anti-HIV-1 activity. The most potent and specific CXCR4 antagonists are the bicyclam derivatives, which also potently block X4 HIV replication. AMD3100 has proved to be a highly specific CXCR4 antagonist, which consistently blocks the outgrowth of all X4 HIV and dual-tropic (R5/X4) variants that use CXCR4 for entering the cells (cell lines, CXCR4-transfected cell lines, lymphocytes or monocytes/ macrophages). From the bicyclam analogues, AMD3100 was selected as the clinical drug candidate, which, after initial Phase I (safety) studies, has proceeded to Phase II (efficacy) trials. The first non-peptidic compound that interacts with CCR5, and not with CXCR4, is a quaternary ammonium derivative, called TAK-779, which also has potent but variable anti-HIV activity. We believe that HIV entry/fusion inhibitors will become important new antiviral agents to combat AIDS. However, like the current clinically approved agents, they will need to be used in combinations consisting of antivirals that target other aspects of the HIV replication cycle, such as reverse transcriptase and protease, to obtain optimum therapeutic effects.
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PMID:Inhibition of HIV infection by CXCR4 and CCR5 chemokine receptor antagonists. 1159 85

Virtually all the compounds that are currently used, or are subject of advanced clinical trials, for the treatment of human immunodeficiency virus (HIV) infections, belong to one of the following classes: (i) nucleoside/nucleotide reverse transcriptase inhibitors (NRTIs): i.e. zidovudine (AZT), didanosine (ddI), zalcitabine (ddC), stavudine (d4T), lamivudine (3TC), abacavir (ABC), emtricitabine [(-)FTC], tenofovir disoproxil fumarate; (ii) non-nucleoside reverse transcriptase inhibitors (NNRTIs): i.e. nevirapine, delavirdine, efavirenz, emivirine; and (iii) protease inhibitors (PIs): i.e. saquinavir, ritonavir, indinavir, nelfinavir, amprenavir and lopinavir. In addition to the reverse transcriptase (RT) and protease reaction, various other events in the HIV replicative cycle can be considered as potential targets for chemotherapeutic intervention: (i) viral adsorption, through binding to the viral envelope glycoprotein gp120 (polysulfates, polysulfonates, polycarboxylates, polyoxometalates, polynucleotides, and negatively charged albumins); (ii) viral entry, through blockade of the viral coreceptors CXCR4 [bicyclam (AMD3100) derivatives] and CCR5 (TAK-779 derivatives); (iii) virus-cell fusion, through binding to the viral envelope glycoprotein gp41 (T-20, T-1249); (iv) viral assembly and disassembly, through NCp7 zinc finger-targeted agents [2,2'-dithiobisbenzamides (DIBAs), azadicarbonamide (ADA)]; (v) proviral DNA integration, through integrase inhibitors such as 4-aryl-2,4-dioxobutanoic acid derivatives; (vi) viral mRNA transcription, through inhibitors of the transcription (transactivation) process (flavopiridol, fluoroquinolones). Also, various new NRTIs, NNRTIs and PIs have been developed that possess, respectively: (i) improved metabolic characteristics (i.e. phosphoramidate and cyclosaligenyl pronucleotides by-passing the first phosphorylation step of the NRTIs), (ii) increased activity ["second" or "third" generation NNRTIs (i.e. TMC-125, DPC-083)] against those HIV strains that are resistant to the "first" generation NNRTIs, or (iii) as in the case of PIs, a different, nonpeptidic scaffold [i.e. cyclic urea (mozenavir), 4-hydroxy-2-pyrone (tipranavir)]. Nonpeptidic PIs may be expected to inhibit HIV mutant strains that have become resistant to peptidomimetic PIs. Given the multitude of molecular targets with which anti-HIV agents can interact, one should be cautious in extrapolating the mode of action of these agents from cell-free enzymatic assays to intact cells. Two examples in point are L-chicoric acid and the nonapeptoid CGP64222, which were initially described as an integrase inhibitor or Tat antagonist, respectively, but later shown to primarily act as virus adsorption/entry inhibitors, the latter through blockade of CXCR4.
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PMID:New developments in anti-HIV chemotherapy. 1208 68

Virtually all the compounds that are currently used or are subject of advanced clinical trials for the treatment of HIV infections, belong to one of the following classes: (i) nucleoside reverse transcriptase inhibitors (NRTIs): i.e., zidovudine, didanosine, zalcitabine, stavudine, lamivudine, abacavir, emtricitabine and nucleotide reverse transcriptase inhibitors (NtRTIs) (i.e., tenofovir disoproxil fumarate); (ii) non-nucleoside reverse transcriptase inhibitors (NNRTIs): i.e., nevirapine, delavirdine, efavirenz, emivirine; and (iii) protease inhibitors (PIs): i.e., saquinavir, ritonavir, indinavir, nelfinavir, amprenavir, and lopinavir. In addition to the reverse transcriptase and protease reaction, various other events in the HIV replicative cycle can be considered as potential targets for chemotherapeutic intervention: (i) viral adsorption, through binding to the viral envelope glycoprotein gp120 (polysulfates, polysulfonates, polycarboxylates, polyoxometalates, polynucleotides, and negatively charged albumins); (ii) viral entry, through blockade of the viral coreceptors CXCR4 (i.e., bicyclam (AMD3100) derivatives) and CCR5 (i.e., TAK-779 derivatives); (iii) virus-cell fusion, through binding to the viral envelope glycoprotein gp41 (T-20, T-1249); (iv) viral assembly and disassembly, through NCp7 zinc finger-targeted agents [2,2'-dithiobisbenzamides (DIBAs), azadicarbonamide (ADA)]; (v) proviral DNA integration, through integrase inhibitors such as 4-aryl-2,4-dioxobutanoic acid derivatives; (vi) viral mRNA transcription, through inhibitors of the transcription (transactivation) process (flavopiridol, fluoroquinolones). Also, various new NRTIs, NNRTIs, and PIs have been developed that possess, respectively: (i) improved metabolic characteristics (i.e., phosphoramidate and cyclosaligenyl pronucleotides by-passing the first phosphorylation step of the NRTIs), (ii) increased activity ["second" or "third" generation NNRTIs ( i.e., TMC-125, DPC-083)] against those HIV strains that are resistant to the "first" generation NNRTIs, or (iii), as in the case of PIs, a different, modified peptidic (i.e., azapeptidic (atazanavir)) or non-peptidic scaffold (i.e., cyclic urea (mozenavir), 4-hydroxy-2-pyrone (tipranavir)). Non-peptidic PIs may be expected to inhibit HIV mutant strains that have become resistant to peptidomimetic PIs.
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PMID:New anti-HIV agents and targets. 1236 88

The potential of a large variety of new compounds and new strategies for the treatment of virtually all major virus infections has been addressed. This includes, for the treatment of HIV infections, virus adsorption inhibitors (cosalane derivatives, cyanovirin-N), co-receptor antagonists (TAK-779, AMD3100), viral fusion inhibitors (pentafuside T-20, betulinic acid derivatives), viral uncoating inhibitors (azodicarbonamide), nucleoside/nucleotide reverse transcriptase inhibitors (NRTIs: emtricitabine, amdoxovir, dOTC, d4TMP prodrugs, tenofovir disoproxil fumarate), non-nucleoside reverse transcriptase inhibitors (NNRTIs: thiocarboxanilide UC-781, capravirine, SJ-3366, DPC 083, TMC 125/R165335), integrase inhibitors (diketo acids), transcription inhibitors (temacrazine, flavopiridol), protease inhibitors (atazanavir, mozenavir, tipranavir); for the treatment of RSV and paramyxovirus infections, viral fusion inhibitors (R170591, VP-14637, NMS03); for the treatment of picornavirus infections, viral uncoating inhibitors (pleconaril); for the treatment of pesti- (hepaci-, flavi-) virus infections, RNA replicase inhibitors (VP-32947); for the treatment of herpesvirus (HSV, VZV, CMV) infections, DNA polymerase inhibitors (A-5021, L- and D-cyclohexenylguanine); for the treatment of VZV infections, bicyclic furopyrimidine analogues; for the treatment of CMV infections, fomivirsen; for the treatment of DNA virus infections at large (papilloma-, polyoma-, herpes-, adeno- and poxvirus infections), cidofovir; for the treatment of influenza, neuraminidase inhibitors (zanamivir, oseltamivir, RWJ-270201); for the treatment of HBV infections, adefovir dipivoxil; for the treatment of HBV and HCV infections, N-glycosylation inhibitors (N-nonyl-deoxynojirimycin); and, finally, IMP dehydrogenase inhibitors and S-adenosylhomocysteine hydrolase inhibitors, for the treatment of various virus infections, including hemorrhagic fever virus infections.
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PMID:Highlights in the development of new antiviral agents. 1237 77

HIV entry within the cell involves the presence of at least two chemokine co-receptors, the CCR5 and CXCR4 receptors. Viral entry can be inhibited by the natural ligands for CXCR4, the CXC chemokine SDF-1 and CCR5, the CC chemokines RANTES, MIP-1alpha and MIP-1beta, respectively. Much research has been devoted ultimately to the development of small molecule chemokine antagonists that inhibit virus entry within the cell, and constitute in this way novel antiviral medications. The most potent and specific CXCR4 antagonists reported up to now are the bicyclam derivatives, which also potently block X4 HIV replication. One such compound, AMD3100 has proved to be a highly specific CXCR4 antagonist, which consistently blocks the outgrowth of all X4 HIV and dual-tropic (R5/X4) variants that use CXCR4 for entering the cells. From such bicyclam analogues, AMD3100 was selected as the clinical candidate, which, after initial Phase I studies, proceeded to Phase II trials, but unfortunately showed significant cardiac side effects which lead to its withdrawal from further development. The first nonpeptidic compound that interacts with CCR5, but not with CXCR4, is a quaternary ammonium derivative, TAK-779, which also shows potent but variable anti-HIV activity. A large number of potent CCR5 antagonists from several classes of polycyclic derivatives have been recently disclosed. Many such derivatives showed nanomolar binding affinity to the receptor, and at least one of them, the oxime-piperidine derivative SCH-351125 has progressed to clinical evaluation. The development of such agents for clinical use may constitute an additional approach for the treatment of HIV infection, in addition to the classical one involving reverse transcriptase and protease inhibitors.
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PMID:Non-peptidic chemokine receptors antagonists as emerging anti-HIV agents. 1242 Jul 52

CCR5-using (R5) human immunodeficiency virus type 1 (HIV-1) is a major viral population that is transmitted by sexual intercourse and that replicates in infected individuals during the asymptomatic stage of HIV-1 infection, suggesting that agents effective against R5 HIV-1 can be expected to prevent viral transmission and delay disease progression. However, R5 HIV-1 is unable to replicate in human T-cell lines, which is an apparent obstacle to efficient and reliable susceptibility tests of compounds for their activities against R5 HIV-1. To establish a simple and rapid assay system for the monitoring of R5 HIV-1 replication and drug susceptibility, we have established a novel reporter T-cell line, MOCHA (which represents MOLT-4 cells stably expressing CCR5 and carrying the HIV-1 long terminal repeat-driven secretory alkaline phosphatase). Cells of this cell line express CD4, CXCR4, and CCR5 on their surfaces and secrete human placental alkaline phosphatase into the culture supernatants during HIV-1 infection. MOCHA cells proved to be highly permissive for the replication of R5 HIV-1 as well as CXCR4-using (X4) HIV-1, and the alkaline phosphatase activity increased in parallel with increasing HIV-1 p24 antigen levels in the culture supernatants. When HIV-1 reverse transcriptase inhibitors, protease inhibitors, and entry inhibitors, including the CCR5 antagonist TAK-779 and the CXCR4 antagonist AMD3100, were examined for their inhibitory effects on R5 and X4 HIV-1 replication in MOCHA cells, the antiviral activities of these compounds were found to be almost identical to those previously reported in peripheral blood mononuclear cells. Thus, MOCHA cells are an extremely useful tool for detection of R5 and X4 HIV-1 replication and drug susceptibility tests.
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PMID:Novel reporter T-cell line highly susceptible to both CCR5- and CXCR4-using human immunodeficiency virus type 1 and its application to drug susceptibility tests. 1279 75


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