An Endogenous Oncornavirus of Guinea Pigs : Its Expression in Leukemic Cells

Nayak, D P; Murray, Paul G.; Goldblatt, David; Karpov, K.

doi:10.1159/000397572

Cited by 3 publications

(4 citation statements)

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“…Similar intracisternal particles have been observed in guinea pig fetal germ cells (2), spleen germinal centers of normal guinea pigs (14), and in a chemically induced guinea pig hepatoma (6). Extracellular virus particles have been reported in the tissues of leukemic guinea pigs in the absence of any apparent budding from the plasma membrane (7), as well as in the blood plasma of the guinea pigs carrying the transplantable leukemia (23). Feldman and Gross (7) have hypothesized that a process of reverse pinocytosis could account for the release of intracisternal virus from leukemic cells in light of the absence of observed budding of virus from the plasma membrane.…”

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confidence: 58%

“…The L2C strain of a transplantable guinea pig leukemia arose spontaneously in 1954 (3) in the strain 2 inbred line of guinea pigs and has since been serially transferred in this strain. Intracellular and extracellular virus-like particles were later observed in these tumor cells (21,23). The intracellular particles are formed by budding through the rough endoplasmic reticulum membrane into intracisternal spaces (7).…”

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confidence: 99%

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Characterization of the oncornavirus particles in the plasma of guinea pigs with L2C leukemia

Scholom¹,

Pearson²,

Perk³

et al. 1976

J Virol

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The inoculation of L2C guinea pig leukemia cells into strain 2 guinea pigs results in the death of the animals within 12 to 15 days. Death is preceded by the simultaneous appearance in the plasma of (i) elevated leukocyte levels, (ii) extracellular virus particles, and (iii) a particle-associated RNA-directed DNA polymerase. This enzyme activity has a cation preference identical to that of the type B bromodeoxyuridine-induced guinea pig virus, i.e., an Mg2+ optimum at 20 mM and no activity using Mn2. Competitive molecular hybridization studies also revealed that the plasma of leukemic guinea pigs contained approximately 2 x 109 genome equivalents per ml of an RNA that is homologous to the RNA of the bromodeoxyuridine-induced guinea pig virus. Morphological observations indicate that most, but not all, of the extracellular particles observed in leukemia plasma are derived from the intracisternal particles seen in the L2C tumor cells. The possibilities that either two viral populations are present or that the in vivo morphogenesis of the type B bromodeoxyuridine-inducible guinea pig virus is markedly different from its in vitro morphogenesis are discussed.

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confidence: 58%

mentioning

confidence: 99%

Characterization of the oncornavirus particles in the plasma of guinea pigs with L2C leukemia

Scholom¹,

Pearson²,

Perk³

et al. 1976

J Virol

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“…Utilizing electron microscopy as well as enzymatic and radioactive labeling techniques, we have not detected the production of virus particles in noninduced guinea pig fibroblast cultures (21). Studies from this laboratory have demonstrated that since there is not an increase in virus specific DNA copies in BUdRtreated cells, GPV induction is due to the expression of endogenous genetic information rather than infection by virus produced at an undetectable level in noninduced cells (22). Thus, these induced virus particles offer a unique opportunity to analyze the expression of cryptic viruses present in mammalian cells.…”

Section: Discussionmentioning

confidence: 82%

“…The biological activity of BUdR-induced GPV is as yet unknown. Intracellular particles resembling GPV have been observed in strain 2 leukemic lymphoblasts and sarcoma cells induced with methylcholanthrene in strain 2 guinea pigs (22). Leukemic lymphoblasts also release particles containing reverse transcriptase at a density of 1.16 g/ml.…”

Section: Discussionmentioning

confidence: 95%

Characterization of Bromodeoxyuridine-Induced Endogenous Guinea Pig Virus

Murray

Nayak

1974

J Virol

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An endogenous virus (GPV) was induced after 5-bromodeoxyuridine treatment of cultured guinea pig cells. Compared to Gross murine leukemia virus (G-MuLV) GPV has a reproducibly heterogenous density of about 1.16 to 1.18 g/ml. The virion-associated RNA is slightly larger than that in G-MuLV. Sodium dodecyl sulfate-polyacrylamide gel electrophoretic analysis of dissociated GPV resolved five major structural proteins: I (molecular weight 70,000), II (molecular weight 36,000), III (molecular weight 24,000), IV (molecular weight 18,000), and V (molecular weight 16,000) which are similar to but distinct from G-MuLV proteins. Proteins I and II were demonstrated to be glycoproteins by incorporation of [3H ]glucosamine. GPV and G-MuLV did not have any appreciable genetic homology or any common group-specific antigens when analyzed by immunodiffusion, radioimmunoassay, and indirect immunofluorescence. Morphogenesis of GPV also differed from that of a typical type C oncornavirus and proceeded via two pathways: (i) a majority of virus particles were formed in cytoplasmic vacuoles and were released after cellular disruption; and (ii) a minor population of particles were assembled in the cytoplasmic matrix and then migrated to the plasma membrane where they budded into the extracellular space. To date, GPV has been unable to initiate or maintain a productive replication in any cell line tested.

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Experimental Models of Lymphoid Malignancies

Peterson

1978

The Immunopathology of Lymphoreticular Neoplasms

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An Endogenous Oncornavirus of Guinea Pigs : Its Expression in Leukemic Cells

Cited by 3 publications

References 0 publications

Characterization of the oncornavirus particles in the plasma of guinea pigs with L2C leukemia

Characterization of the oncornavirus particles in the plasma of guinea pigs with L2C leukemia

Characterization of Bromodeoxyuridine-Induced Endogenous Guinea Pig Virus

Experimental Models of Lymphoid Malignancies

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