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)

After immunization of rabbits the antiserum was prepared against purified reverse transcriptase (revertase) from avian myeloblastosis virus (AMV). The antiserum demonstrated enzymeneutralizing antibody activity that was associated with ummunoglobulin G fraction but not with IgM. The high antigenicity of AMV revertase for rabbits was shown. The active antiserum was obtained after 4 immunizations of rabbit with approximately 20 microgram of the enzyme. Non-specific revertase inhibitors were found in normal rabbit serum, which were absent in IgG fraction from this serum. The revertase activity of Rauscher leukemia virus (RLV) and Visna virus was not neutralized by antisera against AMV polymerase. This work was supported by the project "Revertase".
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PMID:[Immunologic aspects of preparation of antiserum to the reverse transcriptase from avian myeloblastosis virus]. 8 6

An African lioness from the Zoo of Zurich had to be euthanized because of an inoperable tumor. The serum tested negative for feline leukemia virus (FeLV) p27 antigen by enzyme-linked immunosorbent assay (ELISA) but was strongly positive for feline immunodeficiency virus (FIV) antibodies by ELISA and Western blot. When her only offspring and mate were tested for FIV, high antibody titers to FIV were also found in their serum. Lymphocytes were prepared from these two lions on different occasions and co-cultivated with specific pathogen free (SPF) cat lymphocytes in the presence of concanavalin A and recombinant human interleukin-2 (IL-2) for 6 weeks. The cell culture supernatants tested negative for Mg(2+)-dependent reverse transcriptase and FIV p24 by a double antibody sandwich ELISA throughout the culture period. Whole blood and buffy coat cells collected from these two lions were transmitted by intraperitoneal injection into two SPF cats. The two cats did not seroconvert for a period of 11 months nor could reverse transcriptase activity and FIV p24 antigen be demonstrated in the supernatant of several lymphocyte cultures. To determine the importance of lentivirus infections in zoo-kept wild felids, 124 serum samples were obtained from African lions, Indian and Siberian tigers, snow leopards, panthers, cheetahs and other wild cats from nine European zoos. In addition, serum samples collected from 12 Asiatic lions originating from Gir forest in the Indian State of Gujarat were included in this study. The sera were tested for antibodies to FIV, FeLV and feline syncytium-forming virus (FeSFV) by ELISA and Western blot using the respective viruses after gradient purification. In addition, some of the sera were also tested for antibodies to equine infectious anemia virus (EIAV) and Visna-Maedi virus (VMV). Antibodies to FIV were found in 30/53 (57%) of African lions, one of 18 tigers and one of four panthers. All other sera including those collected from the 12 Asiatic lions were negative for FIV antibodies. Some of the FIV positive lion sera had high antibody titers producing strong bands on Western blot strips even in dilutions of >> 1:1000. The Western blot pattern of the lion sera differed from that of domestic cats in that primarily p24 and to a lesser degree p17 was recognized. Antibodies to FeSFV were found in 14 animals (seven with strong, seven with intermediate, reaction). No correlation was found between FIV and FeSFV infection. Antibodies to FeLV were found in two cheetahs which later turned out to have been vaccinated with Leukocell, a FeLV vaccine.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Retrovirus infections in non-domestic felids: serological studies and attempts to isolate a lentivirus. 133 98

HTLV-1, HIV-1 and HIV-2 western blot analysis of sera from patients with multiple sclerosis (MS), from patients with other neurological diseases and from blood donors, revealed a rather frequent cross-reactivity with retroviral proteins in the MS group, though no patient was positive with the corresponding specific ELISA serology. Statistical analysis revealed a significant difference between the MS group and the two control groups for HIV-1 and HIV-2 reverse transcriptase fragments and for HTLV-1 p24. The general significance of these observations is discussed in the light of a retroviral hypothesis for the aetiology of MS. It is suggested that, if a retrovirus is present in MS patients, it does not necessarily belong to the HTLV sub-family and could as well be a lentivirus, like Visna virus, the causative agent of a demyelinating disease in sheep which is one--natural--model for MS.
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PMID:Antibody to reverse transcriptase of human retroviruses in multiple sclerosis. 172 34

We have studied the effects of recombinant human alpha A interferon (IFN) on the multiplication of Visna retrovirus in ovine cells. Pretreatment with IFN followed by continuous IFN treatment, drastically blocked the Visna virus induced cytopathogenic effect and the emergency of neoformed virions. Thus, virus yield and virus dependent reverse transcriptase activity were highly reduced in supernatant fluids. All these effects were accompanied by a strong inhibition of viral protein synthesis. In the light of these data, human IFN action on Visna retrovirus seems to be determined by a mechanism of action distinct from that described in the case of other Retroviridae.
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PMID:Effect of recombinant human alpha A interferon on Visna virus multiplication in acutely infected ovine cells. 256 Mar 15

[(3)H]DNA copies of avian, feline, murine, and primate RNA tumor virus genomes were synthesized in vitro by an RNA-dependent DNA polymerase reaction. These DNAs were hybridized to 60-70S RNA that had been purified from the viruses. The amount of the [(3)H]DNA hybridized yielded a measure of the genetic relatedness among the DNA preparations synthesized by the viruses. When many combinations of DNA and RNA were analyzed, the pattern of hybridization showed in some cases that the DNA copies of the viral RNA were related to each other in the same way that the natural hosts of the viruses are phylogenetically related. This pattern was observed only among the RNA leukemia viruses. The sarcoma component in sarcoma-leukemia viruses from rats and primates appeared to be unusually closely related. The mouse mammary carcinoma virus and two unclassified viruses (MPMV and Visna) appeared to be genetically distinct.A similar analysis of DNA synthesized by an RNA-dependent DNA polymerase associated with a viral-like particle obtained from the cytoplasm of human leukemic white blood cells demonstrated that this DNA occupied a space in the affinity pattern of leukemia viruses which is expected of a nucleic acid from a primate-type-C RNA tumor virus. This observation strengthens earlier evidence that components of RNA tumor viruses are associated with human leukemia.
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PMID:Systematics of RNA tumor viruses and virus-like particles of human origin. 413 60

The presence is reported of an RNA-instructed DNA polymerase in visna virus, the causative agent of a "slow" neurological disease in sheep. The product synthesized by the RNA-directed reaction has been shown to be a DNA heteropolymer by the following criteria: synthesis requires the presence of all four deoxyriboside triphosphates; the product is resistant to ribonuclease and alkali but is degraded by DNase; and the product has a density of 1.420 in Cs(2)SO(4) solution, characteristic of DNA.Visna virions, like those of the oncogenic RNA viruses, contain DNA polymerase activities that respond to a variety of double-stranded DNAs and to synthetic DNA.RNA hybrids.
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PMID:DNA polymerase activities in varions of visna virus, a causative agent of a "slow" neurological disease. 499 14

Visna virus is a retrovirus which replicates in fibroblast-like cells of the sheep choroid plexus through a lytic cycle. Visna virions contain three major low-molecular-weight proteins (p30, p16, and p14) which, together with the genomic RNA and several molecules of reverse transcriptase, constitute the core structure of the virions. The core is surrounded by an envelope containing a major glycoprotein (gp135). By analogy with the oncoviruses, these three groups of structural proteins (i.e., the internal proteins, the envelope glycoprotein, and the reverse transcriptase) are probably encoded by the gag, env, and pol genes, respectively. To elucidate the genetic organization of the visna virus genome and its expression, we studied the synthesis of viral proteins in infected sheep choroid plexus cells. Intracellular viral proteins were detected by immunoprecipitation of pulse-labeled cell extracts with monospecific sera raised against p30, p16, and gp135 and resolution of the proteins by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Immunoprecipitation with anti-p30 and anti-p16 sera allowed the characterization of the 55,000-dalton polypeptide precursor to internal virion proteins p30, p16, and p14 (Pr55(gag)). Tryptic peptide mapping confirmed the precursor-product relationship between Pr55(gag) and the three internal proteins. In addition, a gag-related polypeptide of 150,000 daltons was also detected. This polypeptide, which was less abundant than Pr55(gag), is a likely precursor to the viral reverse transcriptase (Pr150(gag-pol)). Pr55(gag) and Pr150(gag-pol) are not glycosylated. The precursor related to major envelope protein gp135 is a glycosylated polypeptide with an average molecular weight of 150,000 (gPr150(env)). Pulse-chase experiments indicated that gPr150(env) matures into glycoprotein gp135 intracellularly; however, gp135 was never preponderant in cell extracts. The non-glycosylated from of gPr150(env), which accumulated in the presence of 2-deoxy-d-glucose, appeared as a polypeptide of about 100,000 daltons. These results indicated that visna virus codes for the largest non-glycosylated env-related precursor among all of the retroviruses and therefore probably contains the largest env gene.
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PMID:Precursor polypeptides to structural proteins of visna virus. 617 45

Visna-maedi virus induces in sheep an interstitial lung disease characterised by an accumulation of smooth muscle cells (SMC) or myomatosis. Infection by HIV-1 has been recently associated with disorders of the vessel-derived cells: primary pulmonary hypertension, coronary artery disease and smooth muscle tumors in humans. We hypothesized that, besides their regular targets (i.e. macrophages and lymphocytes), lentiviruses could infect smooth muscle cells. Smooth muscle cell cultures derived from ovine aorta were infected with visna-maedi virus strain K1514. The cultured cells were smooth muscle cells as demonstrated by their antigenic expression of alpha-actin and vimentin. The lentiviral infection of the smooth muscle cells was demonstrated by a typical cytopathic effect (syncytia), the expression of virus specific antigens, and the presence of genomic RNA detected by Northern blot analysis and RT PCR. The detection of a reverse transcriptase activity, the presence of viral RNA in supernatants of infected smooth muscle cells detected by RT PCR and their ability to infect ovine permissive fibroblasts demonstrated a productive infection. The ability of smooth muscle cells to be infected by lentiviruses may participate in the pathogenesis of the tissue damage associated with the lentiviruses such as myomatosis in sheep and vascular disease in humans.
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PMID:Ovine aortic smooth muscle cells allow the replication of visna-maedi virus in vitro. 754 8

The goal of this report was to describe the clinical signs and diagnosis of Visna in a seven-year-old East Friesian milk sheep. A striking feature was that the ewe's behaviour changed frequently. At one time, the ewe was somnolent. A few minutes later, the sheep was alert and eating hay. The ewe was thin. It had a slight head tilt and a severe generalised ataxia. Based on the neurological symptoms and chronic weight loss, a tentative diagnosis of visna was made. Serological testing for maedi-visna was positive, and the ewe was euthanised. A postmortem examination was performed, and lung and brain samples were collected aseptically. Cell cultures from these organs were positive for viral enzymatic reverse transcriptase and for maedi-visna RNA.
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PMID:[Clinical findings and diagnostic procedure in a dairy sheep with visna]. 1172 74

AdUTPase gene ( du) deleted ovine lentivirus (OvLV(Deltadu)) mutant, derived from Visna/maedi virus (VMV) molecular clone KV1772, was constructed. Subsequently, a copy of the optimized green fluorescent protein ( egfp) coding region was fused into the viral pol open reading frame (ORF) at the deleted du locus to generate viral mutant, OvLV(Deltadu-egfp). OvLV(Deltadu) reverse transcriptase (RT) activity and titer of infectious virus in goat synovial membrane (GSM) cell cultures were not affected compared to that of KV1772 and OvLV-85/34 strain (p < 0.05). By contrast, OvLV(Deltadu-egfp) RT activity and virus titer were lower than for KV1772 and OvLV(Deltadu) (p < 0.05). OvLV-85/34 RT in sheep monocyte-derived macrophages (SMDM) was higher than that of KV1772, OvLV(Deltadu) and OvLV(Deltadu-egfp) (p < 0.05). The ability to prevent dUTP mis-incorporation into newly synthesized DNA was disrupted in OvLV(Deltadu) and OvLV(Deltadu-egfp) (p < 0.05). Immunoprecipitation demonstrated that GFP is expressed by OvLV(Deltadu-egfp) at a low level. OvLV(Deltadu-egfp) retained egfp after 10 passages in cell culture.OvLV(Deltadu-egfp) was re-isolated in GSM cells from peripheral blood mononuclear (PBMN) cells of three of four OvLV(Deltadu-egfp)-inoculated lambs, but by contrast to the in vitro experiments OvLV(Deltadu-egfp) lost the insert. Priming with OvLV(Deltadu-egfp) did not prevent infection with pathogenic OvLV, but cell-associated viremia in a mock-infected contact control lamb was higher than in OvLV(Deltadu-egfp)-primed lambs. OvLV serum antibody titers increased steadily in OvLV(Deltadu-egfp)-inoculated lambs, but in a lamb from which OvLV(Deltadu-egfp) was not reisolated the antibody titer surpassed the negative/positive cut-off value only after challenge with OvLV-85/34. Because OvLV(Deltadu-egfp) is attenuated for pathogenicity in vitro, replicates in vivo and stimulates an antibody response, subsequent experiments need to address the likelihood of using OvLV(Deltadu-egfp) as an attenuated, live-virus vaccine to protect sheep against OvLV-induced disease when challenged with pathogenic OvLV.
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PMID:Construction and characterization of a recombinant ovine lentivirus carrying the optimized green fluorescent protein gene at the dUTPase locus. 1289 27


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