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)

Nervous system tissues from a number of patients with idiopathic neurological disorders were examined for biochemical evidence of RNA tumor virus infection. RNase-sensitive DNA polymerase activity was found in a cytoplasmic particulate fraction from two patients with Guamanian amyotrophic lateral sclerosis (ALS) but not in brains from two normal U.S. individuals. The buoyant density of the enzyme-containing fraction was 1.16-1.18 g/ml and could be converted to a denser region of the gradient (1.24 g/ml) by treatment with the nonionic surfactant, Sterox. The cation and detergent requirements for the endogenous RNase-sensitive DNA polymerase reaction were determined. The early (5 min) endogenous reverse transcriptase product was analyzed by cesium sulfate gradient centrifugation. RNase- and heat-sensitive RNA-DNA hybrids were detected in the product analysis of two ALS, one Parkinsonism-dementia (PD) brain, and two brains from asymptomatic Chamorros but not in brains from normal U.S. individuals and a number of patients with neuro-psychiatric disorders. The DNA product was a 4.5S heteropolymer that hybridized more extensively to RNA extracted from the enzyme-containing pellet from PD brain as compared to a similar fraction from normal U.S. brain. The DNA product appeared to be unrelated to Rausvher or visna virus 70S RNA as determined by RNA-[-3H]DNA hybridization.
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PMID:RNA-instructed DNA polymerase activity in a cytoplasmic particulate fraction in brains from Guamanian patients. 4 90

Revistin, a substance that strongly inhibits the reverse transcriptase activity of murine leukemia virus in our screening system, was obtained from a cultured broth of a soil streptomyces which was closely related to Streptomyces filipinensis. The assay method for the activity was based on the inhibition by a test material of the incorporation of 3H-dTMP into DNA synthesized by the reverse transcriptase of an oncogenic RNA virus. Crude revistin was isolated by serial procedures of salting out with ammonium sulfate and precipitation with cetylpyridinium chloride. The crude material showed neither antibacterial nor antifungal activity. It exhibited against splenomegaly in mice caused by Rauscher leukemia virus infection.
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PMID:Revistin found by screening for inhibitors of reverse transcriptase of an oncogenic virus. 5 48

A cytoplasmic particulate fraction from human leukemic cells has been shown to contain reverse transcriptase and its associated high-molecular weight RHA template. We attempted to detect the reverse-transcriptase-template complex in morphologically normal peripheral blood leukocytes from patients with acute leukemia in complete remission. Our assay system consisted of a velocity glycerol gradient and cesium sulfate equilibrium gradient analysis of the endogenous reverse transcriptase reaction product. Three of nine patients in remission had positive reactions determined by glycerol gradient analysis, and eight of 10 patients in remission had positive reactions by cesium sulfate gradient analysis. We were unable to detect the template complex in leukocytes of normal persons. Thus, normal-appearing leukocytes in the peripheral blood of some leukemia patients in remission seem to retain a number of biochemical characteristics, possibly viral related, associated with leukemic cells.
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PMID:Reverse transcriptase in leukocytes of leukemic patients in remission. 5 87

The alpha beta DNA polymerase of avian myeloblastosis virus was treated with dimethyl sulfoxide to dissociate the enzyme subunits. The dimethyl sulfoxide treated enzymes were passed over phosphocellulose to purify and characterize the dissociated subunits as well as to remove the dimethyl sulfoxide. RNA-directed DNA polymerase, RNase H, and nucleic acid-binding activity were monitored, as well as the subunit structure (on sodium dodecyl sulfate-polyacrylamide gels) of the various enzyme species obtained. With 30% dimethyl sulfoxide, the majority of DNA polymerase and RNase H activities as well as the alpha subunit were displaced from the alpha beta DNA polymerase position on phosphocellulose (0.23 M potassium phosphate) to the alpha DNA polymerase position (0.1 M). The association of DNA polymerase and RNase H activities with the alpha subunit suggests that alpha is the enzymatically active subunit in alpha beta. In addition to alpha DNA polymerase, a minor polymerase species eluted from phosphocellulose at 0.4 M potassium phosphate. The dissociated beta subunit eluted from phosphocellulose at a wide range of salt concentrations (0.28 to 0.5 M potassium phosphate). The dissociated beta subunit bound 3H-labeled murine leukemia virus RNA and [3H]poly(dT)-poly(dA) approximately 20-fold more avidly than alpha DNA polymerase alone. In contrast to the results with the alpha subunit, there was no correlation between DNA polymerase and RNase H activity profiles and the elution profile of the beta subunit from phosphocellulose. These observations suggest the beta subunit is either enzymatically inactive or possesses limited DNA polymerase and RNase H activity when compared with the alpha subunit.
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PMID:Dissociation of alpha beta DNA polymerase of avian myeloblastosis virus by dimethyl sulfoxide. 5 61

The sulfated glycosaminoglycans chondroitin 4-sulfate, chondroitin 6-sulfate, keratan sulfate, dermatan sulfate, heparin, and glycosaminoglycan polysulfate are competitive inhibitors of the DNA-dependent RNA polymerase, the DNA-dependent RNA polymerase and the RNA-dependent DNA polymerase (reverse transcriptase). The unsulfated glycosaminoglycans chondroitin and hyaluronate are without any influence on the synthesis of DNA and RNA. The strongest inhibitor is a glycosaminoglycan polysulfate with four sulfate groups per disaccharide unit. It has the following inhibitor constants: DNA polymerase, Ki = 1.5 X 10(-6) M; RNA polymerase, Ki = 0.9 X 10(-6) M; reverse transcriptase, Ki = 1.1 X 10(-6) M. The inhibition is closely correlated to the degree of sulfation of the glycosaminoglycans. There is a relationship between the sulfate/hexosamine ratio and the degree of inhibition. The inhibition of the DNA and RNA synthesizing enzymes by sulfated glycosaminoglycans depends on the nature of the template. With double-stranded DNA as template, inhibition occurs only when sulfated glycosaminoglycans are added before or shortly after (30 s) initiation of the synthesis. There is no inhibition if the inhibitors are added after the onset of the synthesis. On the other hand, with a single-stranded template synthesis was blocked completely at each phase of reaction.
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PMID:Interactions of glycosaminoglycans with DNA and RNA synthesizing enzymes in vitro. 6 Nov 58

Subviral cores have been prepared from the oncornavirus-like particle found in human milks with the use of phospholipase C and ether or Sterox SL. The major protein of these cores has a molecular weight of 27,000 daltons, as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. This protein is found in the core fractions of reverse transcriptase-positive milks and is absent in negative milks. It is distributed in sucrose gradients only in those fractions containing cores and reverse transcriptase activity. The major core protein of the human milk oncornavirus-like particle is electrophoretically identical to the major core protein of the mouse mammary tumor virus.
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PMID:Identification and isolation of the major core protein from the oncornavirus-like particle in human milk. 6 99

A protein kinase associated with purified virions of avian myeloblastosis virus, BAI strain A, was highly purified by ion-exchange chromatography and gel filtration. On the basis of molecular sieving on Sephadex G-200, the enzyme protein appeared to have a molecular weight of about 50,000 to 60,000; disc gel electrophoresis in sodium dodecyl sulfate-acrylamide gels revealed the presence of at least two polypeptide chains; and isoelectric focusing on acrylamide gels revealed two protein bands with activity. Of the nonviral proteins used as phosphate acceptors, the greatest rate of phosphorylation was obtained with alpha-casein. Potential physiological substrates for this activity included specific virion polypeptide of avian myeloblastosis virus. One of the virion polypeptides found in association with reverse transcriptase activity from avian myeloblastosis virus accepted more phosphate than any of nonviral or viral polypeptides examined on the basis of nanomoles of 32P incorporated per milligram of protein.
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PMID:Protein kinase and phosphoproteins of avian myeloblastosis virus. 6 29

An RNA-directed DNA polymerase was found to be associated with intracytoplasmic A-particles from DBA/2 mouse leukemia cells. The enzyme activity was detected after disrupting the purified particles with 2 M NaCl-20 mM dithiothreitol. The presence of a divalent cation and all four deoxyribonucleoside triphosphates was essential for this enzyme activity. The enzyme had a clear preference for Mg2+ over Mn2+. Cesium sulfate isopycnic gradient centrifugation of the DNA product synthesized in the actinomycin D-containing reaction revealed the presence of DNA-RNA hybrid. Furthermore, the purified DNA product was found to hybridize with RNA isolated from A-particles. These observations strongly indicate that the endogenous A-particle RNA serves as the template for the DNA polymerase.
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PMID:Characterization of an RNA-directed DNA polymerase found in association with murine intracytoplasmic A-particles. 6 24

A new retravirus (SMRV) isolated from a squirrel monkey, Saimiri sciureus, has an Mg2+-dependen reverse transcriptase and a buoyant density of 1.17 g/cm3 in sucrose and 1.21 g/cm3 in cesium chloride, similar to the mouse mammary tumor virus and the Mason-Pfizer monkey virus. The polypeptide patter of SMRV as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis was distinct from the reported polypeptide patterns of known retraviruses. Four major polypeptides of molecular weights 40,000, 20,000, 14,000 and 8,000 were resolved in virus propagated in human, mink, and canine cells. In A204 human rhabdomyosarcoma cells, a protein of 73,000 daltons (gp73) represented the major viral glycoprotein as determined by [3H]glucosamine labeling. Additional proteins were also observed, but their presence depended on the cell type in which the virus was propagated. In both species-and interspecies-specific assays, no antigenic relatedness was observed between SMRV and Mason-Pfizer monkey virus, mouse mammary tumor virus, baboon endogenous virus (BaLV), woolly monkey virus (SSV-1), murine leukemia virus, endogenous feline type C virus (RD-114), bovine leukemia virus, and equine infectious anemia virus. These findings indicate that SMRV represents a new retravirus and the first isolate from a New World monkey.
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PMID:Characterization of a retravirus isolated from squirrel monkeys. 6 28

From the same batch of virus, the four major avian viral structural proteins p27, p19, p15, and p12, the reverse transcriptase, the envelope glycoprotein gp85, and the high molecular weight 70 S RNA have been recovered. All proteins, except for gp85, have been purified by use of column chromatography procedures to apparent homogeneity as judged by sodium dodecyl sulfate-polyacrylamide gels and isoelectric focusing. A new isolation procedure for p12 by affinity column chromatography takes advantage of its nucleic acid binding properties. The recovery of nondenatured viral structural proteins is demonstrated by the proteolytic activity revealed by p15. The purified proteins were used for the production of monospecific antibodies. The 70 S RNA served as source for the isolation of 35 S RNA subunits.
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PMID:The isolation of avian viral RNA and polypeptides. 8 39


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