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:3.1.30.2 (endonuclease)
18,621 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The gag and pol genes of the human immunodeficiency virus type 1 (HIV-1) (ref. 1) are translated as two polyproteins, Pr55gag and Pr160gag-pol (refs 2-6), which are subsequently cleaved by the action of a virus-encoded protease into the four structural gag proteins of the virion core (p17, p24, p7 and p6) and the pol-encoded enzymes essential for retrovirus replication (protease, reverse transcriptase, ribonuclease H, and endonuclease). Mutational inactivation of the proteases of HIV-1 and other retroviruses results in immature, non-infectious virions, indicating that exogenous inhibition of the protease may represent an attractive approach to anti-AIDS therapy. Here we demonstrate that synthetic peptide analogues, which are potent inhibitors of purified HIV-1 protease, inhibit the processing of the viral polyproteins in cultures of HIV-1-infected T lymphocytes and attenuate viral infectivity.
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PMID:Inhibition of HIV-1 protease in infected T-lymphocytes by synthetic peptide analogues. 168 46

Human immunodeficiency virus type 1 (HIV-1) isolates from asymptomatic homosexual men and AIDS patients were compared for their in vitro biologic and genetic properties. Most of the HIV-1 isolates from asymptomatic men, but not from AIDS patients, failed to infect CD4+ H9 cells and phytohemagglutinin-stimulated peripheral blood lymphocytes. In a longitudinal study, serial HIV-1 isolates obtained from men who seroconverted to HIV-1 and later developed AIDS were able to infect H9 cells. In contrast, longitudinal isolates from men who remained asymptomatic did not infect H9 cells. HIV-1 isolates from AIDS patients in general exhibited increased production of intracellular viral DNA, RNA, and protein as compared to isolates from asymptomatic men. Cells infected with HIV-1 isolates from asymptomatic men produced very little gp120, p24, and p55 proteins as compared to those from AIDS patients. The overall restriction patterns of HindIII, Sac-1, Pst-1, EcoR1, and BamH1 were very similar between HIV-1 isolates from asymptomatic men and those from AIDS patients. However, the restriction endonuclease pattern of BglII was quite distinct for isolates from asymptomatic men as compared to AIDS patients. Preliminary studies mapped a unique BglII site in the gag region of most of the isolates from asymptomatic men, approximately 2.0 kb from the 5' end. Thus, HIV-1 isolates from asymptomatic subjects and from AIDS patients have distinct biologic and genetic properties which may be related to the various clinical outcomes of HIV-1 infection.
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PMID:Human immunodeficiency virus isolates from asymptomatic homosexual men and from AIDS patients have distinct biologic and genetic properties. 170 46

Mutations were introduced by recombinant DNA techniques into 9 genes of an infectious molecular clone of human immunodeficiency virus type 1. The 24 mutants generated were characterized biochemically and biologically by transfection and infection experiments. None of the mutants which have mutations in gag (p17, p24, and p15 regions), pol (protease, reverse transcriptase, and endonuclease domains), env (gp120 region), tat, or rev were infectious, whereas vif, vpr, vpu, some of env (gp41) and nef mutants could grow in human CD4+ cells to various degrees. Of the non-infectious mutants, only endonuclease (pol) and gp41 mutants exhibited normal phenotypes with respect to the production of functional reverse transcriptase, the expression of gag, pol, and env proteins, and the generation of progeny virions, when examined in transient assays. All infectious mutants killed the CD4+ cells with the exception of a mutant carrying a defect in the vif gene.
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PMID:Generation and characterization of the human immunodeficiency virus type 1 mutants. 170 90

In order to characterize novel human immunodeficiency virus type 1 (HIV-1) continuous epitopes, we designed a simple method, based on recombinant DNA, providing a complete set of peptides derived from HIV-1. A library (4 x 10(4) clones) was first constructed in a new expression/secretion vector, using as inserts small fragments of HIV-1 DNA (50-150 bp) generated by random DNAse I cleavage. This peptide library, expressed in the yeast Saccharomyces cerevisiae, was screened with sera of HIV-1 infected individuals and human and murine anti-HIV-1 monoclonal antibodies. Plasmids from immunoreactive colonies were recovered and the sequences of the HIV-1 derived inserts were determined. By using human sera, we have detected classical HIV-1 epitopes and identified two novel major epitopes, which may be used to improve diagnostic tests, localized in the p24 core protein and in the endonuclease. In addition, four minor epitopes were also defined by screening the library with monoclonal antibodies: in the protease, in the p17 core protein, in gp120 and near the C-terminal of gp41. This method is general and can be used for any protein from which a cloned cDNA is available.
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PMID:A peptide library expressed in yeast reveals new major epitopes from human immunodeficiency virus type 1. 171 77

Animal cells differ in susceptibility to HIV-1 infection. To identify rodent cells which are permissive to HIV-1 replication, we transfected murine and rat cells with an infectious clone of HIV-1 and a vector containing the chloramphenicol acetyl transferase gene under the control of HIV-1 LTR. Three groups of transfectants were distinguished: (i) Cells which permit neither HIV-1 LTR activation nor viral protein expression; (ii) Cells which permit activation of the HIV-1 LTR but not HIV-1 protein expression; and (iii) Cells which are fully permissive to both HIV-1 LTR activation and virus production. The latter included rat embryonal fibroblastoid (Rat2) cells, which, in short-term transfection assays, produced titers of HIV-1 proteins similar to transfected T lymphoid cells. To establish persistently infected cells, Rat2 cells were stably transfected with a plasmid containing an infectious clone of HIV-1/N1T-A and a neo gene, yielding several G-418-resistant, HIV-1-producing cell cultures. Of these, Rat2/A1 and Rat2/A2 cell cultures expressed up to 60 ng HIV-1 p24 core antigen per 1 x 10(6) cells 3 days after cell subculture over a period of 3 months. Southern blot hybridization revealed that Rat2/A1 and Rat2/A2 carried one to two HIV-1 DNA copies per cell; no rearrangements or deletions in viral DNA were present. Restriction endonuclease analysis of HIV-1 DNA in Rat2/A2 cells suggested clonal expansion of cells containing integrated HIV-1 genome. Virus produced by the Rat2/A1 cells was infectious in human T cells. These data demonstrate that some rodent cells have no inherent restriction to persistent and efficient production of infectious HIV-1.
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PMID:The establishment of rodent cell lines persistently producing HIV-1. 172 96

We evaluated the use of the INNO-LIA HIV-1/HIV-2 Ab test (LIA HIV; Innogenetics) for the confirmation of antibodies to human immunodeficiency virus type 1 (HIV-1) and type 2 (HIV-2). The test includes three recombinant HIV-1 proteins: p24 (gag), p17 (gag), and endonuclease (p31; pol), in combination with two synthetic peptides derived from the env gene of HIV-1 and one synthetic peptide selected from the env gene of HIV-2. Analysis of 450 sera from blood donors, 220 sera from patients with non-HIV pathology, and 28 Western blot (WB) p24-only reactive sera revealed no false-positive results, and the rate of indeterminate results was substantially lower than that with WB. Testing of 334 WB-confirmed HIV antibody-positive sera (309 HIV-1; 25 HIV-2) revealed no false-negative results. In two of seven seroconversion panels tested, LIA HIV detected the presence of HIV antibodies before WB did. In the other five panels, LIA HIV and WB confirmed the presence of HIV antibodies in the same sample. The LIA HIV assay therefore appears well suited for routine confirmation of the presence of HIV-1 and HIV-2 antibodies.
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PMID:Confirmation and differentiation of antibodies to human immunodeficiency virus 1 and 2 with a strip-based assay including recombinant antigens and synthetic peptides. 191 62

An ELISA procedure is described for the quantification of intrathecally synthesized immunoglobulin G antibodies to human immunodeficiency virus (HIV) antigens. Recombinant p17, p24, endonuclease (END), reverse transcriptase (RT), a peptide from the transmembrane region of gp41 (ENV80) and a fusion protein containing HIV-1 and HIV-2 epitopes were compared with a commercially available ELISA. Using a reference serum, antibodies in serum and cerebrospinal fluid (CSF) to all of the antigens could be measured quantitatively in a reliable and reproducible fashion. Despite the fact that the titer varied up to 10(5)-fold between CSF and serum, interassay variability ranged from 3.87% for p17 to 8.41% for RT and intra-assay variability varied from 3.9% +/- 1.2% for p17 to 14.3% +/- 3.9% for the commercial ELISA. Antibody specificity indices (ASI) obtained by relating CSF/serum titers with reference to the corresponding IgG concentrations can be used to detect intrathecal synthesis of virus specific antibodies.
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PMID:The use of recombinant antigens in ELISA procedures for the quantification of intrathecally produced HIV-1-specific antibodies. 199 6

We report the characterization of a variant of human T-lymphotropic virus type I (HTLV-I) isolated from an interleukin 2-dependent, CD8+ T-cell line derived from peripheral blood mononuclear cells of a healthy member of a remote, recently contacted hunter-horticulturalist group (Hagahai) in Madang province of Papua New Guinea. Antigenic characterization of this variant, designated PNG-1, by immunofluorescence, indicated no expression of gag-encoded proteins p19 and p24 (even after incubation with 5-bromo-2'-deoxyuridine), using monoclonal and polyclonal antibodies against HTLV-I gag gene products. Virus-specific proteins of 15, 19, 46, 53, and 61/68 kDa were demonstrated by Western blot analysis, using sera from patients with serologically and/or virologically confirmed HTLV-I myeloneuropathy, sera from HTLV-I-infected rabbits, and antibodies prepared against the C terminus of the major envelope glycoprotein gp46. Restriction endonuclease maps of PNG-1 proviral DNA differed from that of a prototype strain of HTLV-I (MT-2), but, as verified by polymerase chain reaction, PNG-1 was definitely HTLV-I, not HTLV-II. Nucleotide sequencing and further molecular genetic studies of this variant may provide insights into the origin and evolution of HTLV-I.
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PMID:Characterization of a variant of human T-lymphotropic virus type I isolated from a healthy member of a remote, recently contacted group in Papua New Guinea. 199 44

A HIV-2 strain named HIV-2ben was isolated from peripheral blood lymphocytes of a patient who, since 1984, had developed neurological symptoms such as Raynaud's syndrome, followed by paresthesia of extremities and ataxia, and finally paraparesis of the legs and incontinence. This new isolate could be distinguished from HIV-2rod by antibody-binding epitopes, peptide maps of core p24 and p18 polypeptides and restriction endonuclease cleavage pattern.
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PMID:Isolation and characterization of HIV-2ben obtained from a patient with predominantly neurological defects. 211 42

The antigenic group (Ag) system of homospecific human serum antigens of low density lipoprotein is detected by antiserum from multiply transfused patients. A complex series of common Ag alleles has been described, but the biochemical nature of this polymorphism is uncertain. Here we report that DNA polymorphisms at the human apolipoprotein B (apoB) locus are very closely linked to alleles of the Ag system. We also show a strong association between Ag(x) and a polymorphism detected with the restriction endonuclease Xba I. We conclude that the immunologically determined Ag system represents protein polymorphism of apoB rather than primary genetic differences in posttranslational processing or lipid binding. These studies therefore demonstrate that the Ag locus is located on the short arm of human chromosome 2 in the region p23-p24 to which the apoB gene has been assigned. Since the Ag(x) antigen is associated with altered plasma lipid levels, this determinant may indicate a functionally important domain of apoB.
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PMID:Genetic linkage between the antigenic group (Ag) variation and the apolipoprotein B gene: assignment of the Ag locus. 287 24


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