On visna virus: Purification and nucleic acid content

Lin, Fu Hai; Thormar, Halldór

doi:10.1016/0042-6822(70)90363-6

Cited by 14 publications

(10 citation statements)

References 16 publications

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“…Several apparently "nononcogenic" viruses have been reported to contain the RNA-instructed DNA polymerase (13)(14)(15). This includes visna, an agent that causes a "slow" neurological disease in sheep, and another agent that induces a progressive pneumonia in sheep.…”

Section: Discussionmentioning

confidence: 99%

DNA Polymerase Activities and Nucleic Acid Components of Virions Isolated from a Spontaneous Mammary Carcinoma from a Rhesus Monkey

Schlom

Spiegelman

1971

Proc. Natl. Acad. Sci. U.S.A.

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Virions isolated from a spontaneous mammary carcinoma of a rhesus monkey and propagated in human cells possess an RNA-instructed DNA polymerase. They also exhibit DNA polymerase activities that respond to either double-stranded DNA or synthetic RNA DNA hybrid complexes as templates. The virion has been shown to have a density of 1.16 g/ml and to contain a nucleic acid species of high molecular weight (sedimentation coefficient, 60-70 S), which bands as RNA at 1.670 in a Cs2 SO4 equilibrium density gradient. In addition, the virions contain species of low molecular weight (4-6 S) that consist of RNA as well as components banding at densities characteristic of DNA RNA complexes. The nucleoid of this virion has been isolated and shown to have a density of 1.23 g/ml; it also contains a 60-70S nucleic acid species.The presence of a virus, morphologically similar to that of the known RNA tumor viruses, has been recently reported in a spontaneous mammary tumor of a rhesus monkey (1-4).These particles were initially propagated by cocultivation of the mammary tumor tissue with monkey embryonic cells and they have since been grown in a variety of monkey, chimpanzee, and human cell lines (4,5). This virus has recently been designated the Mason-Pfizer monkey virus (M-PMIV) (6).We have previously shown (7) that these particles contain an RNA-instructed DNA polymerase. We report here on further characterization of the product synthesized and a demonstration that M-P]MV possesses many of the biochemical and biophysical features common to the oneogenic RNA viruses of other species. MATERIALS AND METHODS Virus and cellsThe virus, isolated from a spontaneous monkey mammary tumor, was propagated in suspension cultures of the cell line NC-37, which was established from normal human leukocytes.The medium employed was RPMII 1640, with 10% fetal calf serum and potassium penicillin G (50 units/ml) and streptomycin sulfate (50,4g/ml). All virus for polymerase studies was Glycerol gradient sedimentation analysis Nucleic acid to be examined was pelleted by centrifugation at 23,000 X g for 30 min at 0C, resuspended in 0.5 ml of TNE (0.01 Al Tris * HCl (pH 8.3)-0.1 M NaCl-0.002 M EDTA), and layered onto a previously formed density gradient of 10-30% (v/v) glycerol in TNE. Gradients were centrifuged at 201,000 X g for 2.5 hr at 40C in an SW41 swinging-bucket rotor. 24-drop fractions were collected from below; optical density at 260 nm was measured for each fraction when nucleic acid from unlabeled virions was analyzed; for radioactively labeled material, 50-Md portions were mixed with 0.5 ml of NCS reagent (Amersham/Searle) and radioactivity was counted after addition of toluene-BBOT. 18S and 28S [3H ]RNA extracted from rat embryo fibroblast cells were used as markers in sedimentation analysis. DNA polymerase reactionsThe RNA-instructed polymerase activity, DNA-instructed l)olyrmerase activity, and the polymerase activity employing synthetic RNA -DNA hybrids as templates were all assayed as previously described (7-9). RESULTS Density...

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Section: Discussionmentioning

confidence: 99%

DNA Polymerase Activities and Nucleic Acid Components of Virions Isolated from a Spontaneous Mammary Carcinoma from a Rhesus Monkey

Schlom

Spiegelman

1971

Proc. Natl. Acad. Sci. U.S.A.

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“…Visna virus causes a slow infection of the central nervous system (CNS) of sheep. It is a ribonucleic acid (RNA) virus (9,11), but its proliferation in cell cultures requires deoxyribonucleic acid (DNA) synthesis early in the growth cycle (21) and the virions contain RNAand DNAdependent DNA polymerases (12,17). Visna virus is, therefore, apparently similar to the RNA tumor viruses (1,14,15,17,18,20) in its biochemical properties and also with respect to a number of other characteristics (22).…”

mentioning

confidence: 99%

Characterization of Ribonucleic Acid from Visna Virus

Lin

Thormar

1971

J Virol

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A single-stranded ribonucleic acid(s) has been isolated from purified virions of visna virus. It consists of two major components, namely 63S and "4S," under the conditions employed for ribonucleic acid (RNA) extraction. The 63S component can be converted to subunits by heat and dimethylsulfoxide treatments. Analyses by base composition indicate that the "4S" RNA isolated from visna virus is not a random breakdown product of the 63S component as a result of extraction, nor is it randomly derived from cellular RNA.

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“…TROWBRIDGE, g. LEIII~IANN, C. TORO~IIO, and P. Baol, H-z: 2 hours at 37 ° C and fed an additional 40.0 ml of MSI. Virus in this fluid was precipitated with zinc acetate (9,10,11). The precipitates were recovered by eentrifugation, suspended and dissolved in a saturated solution of disodium-EDTA, and then diaIyzed overnight against TN buffer (0.01 ~ Tris-hydroehloride, 0.1 5~ NaC1, pH 7.4) at 4 ° C. The dialyzed virus suspensions were clarified by low-speed eentrifugation, diluted with TN buffer, and centrifuged at 95,000 × g for t hour.…”

Section: Viral Antigenmentioning

confidence: 99%

Wild-type temperature-sensitive and -resistant visna viruses: Isolation and biological comparison

Trowbridge¹,

Lehmann²,

Torchio³

et al. 1981

Archives of Virology

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The plaques formed by wild-type (WT) populations of strain K485 visna (V-K485) virus, strain K796 visna (V-K796) virus, and of progressive pneumonia virus in sheep choroid plexus (SCP) cell cultures are heterogeneous in size. Plaque purification procedures showed that this heterogeneity was due to the presence of two biologically different viruses, large plaque-forming (Lpf) virus and small plaque-forming (Spf) virus. The V-K796 Lpf virus, the V-K796 Spf virus, and the V-K796 WT virus are antigenically similar to each other. Although the V-K796 Spf virus is less cytopathic than the V-K796 Lpf virus, both viruses have a 14- to 16-hour latent period in SCP cells and have similar rates of synthesis for the initial 24 to 30 hours after infection. The V-K796 Spf virus is considered a temperature-sensitive visna virus since, unlike the V-K796 Lpf virus, it does not produce plaques at 41 degrees C and it is more thermosensitive than the V-K796 Lpf variant. Population analyses of two strains of wild-type visna virus and one strain of progressive pneumonia virus demonstrated that these populations contain variants with the phenotypes of V-K796 Spf virus and V-K796 Lpf virus, that the Spf virus was not selected against in sheep, and that cultivation of the wild type visna viruses at 37 degrees C selected against the temperature-sensitive variants. The existence of the temperature-sensitive Spf viruses in these wild-type virus populations suggests that the Spf variants maintain the persistent visna virus infection in sheep and delay the development of the host's cell-mediated immune response to the viral proteins.

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On visna virus: Purification and nucleic acid content

Cited by 14 publications

References 16 publications

DNA Polymerase Activities and Nucleic Acid Components of Virions Isolated from a Spontaneous Mammary Carcinoma from a Rhesus Monkey

DNA Polymerase Activities and Nucleic Acid Components of Virions Isolated from a Spontaneous Mammary Carcinoma from a Rhesus Monkey

Characterization of Ribonucleic Acid from Visna Virus

Wild-type temperature-sensitive and -resistant visna viruses: Isolation and biological comparison

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