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Proceedings of the National Academy of... Sep 1984Cell lines were derived from ob17 preadipocyte cells by focus formation after transfer of the complete early region of polyoma virus (ob17PY) or of a modified genome...
Cell lines were derived from ob17 preadipocyte cells by focus formation after transfer of the complete early region of polyoma virus (ob17PY) or of a modified genome encoding only the middle T protein (ob17MT). Both ob17PY and ob17MT cell lines exhibited a high cloning efficiency in agarose medium containing 10% fetal bovine serum. Fully transformed ob17PY cells grew to high saturation densities and did not differentiate in vitro and in vivo. ob17MT cells and derived subclones did not grow in the absence of serum and were able to differentiate in vitro and to give rise in vivo to adipose tumors. Among these different clones an inverse relationship was observed in culture between their potentiality to overproliferate at low serum and their potentiality to convert into adipose cells. The expression of enzyme markers of adipose conversion was strictly dependent upon the presence of growth hormone. In addition, the hormonal requirements for differentiation were simpler than those of the original ob17 cells and the adipose conversion could take place in serum-free hormone-supplemented medium.
Topics: Adipose Tissue; Animals; Antigens, Polyomavirus Transforming; Cell Differentiation; Cell Division; Cell Line; Cell Transformation, Neoplastic; Genes; Genes, Viral; Kinetics; Oncogenes; Polyomavirus; Viral Proteins
PubMed: 6089203
DOI: 10.1073/pnas.81.17.5440 -
Infection and Immunity Jul 1976A new viral agent, stumptailed macaque virus (STMV), isolated from uninoculated stumptailed macaque kidney cultures was identified. The virions had the size and...
A new viral agent, stumptailed macaque virus (STMV), isolated from uninoculated stumptailed macaque kidney cultures was identified. The virions had the size and morphology of papovaviruses of the simian virus 40 (SV40)-polyoma subgroup, but many of them appeared to have an additional outer envelope. The deoxyribonucleic acid of STMV was a superhelical circular molecule, with a mean length 91% of that of SV40. The antigenic relationship of this virus with other members of the group was examined by immune electron microscopy of isolated virions and by immunofluorescent staining of virus-infected cells. STMV was immunologically distinct from SV40, BK virus (BKV), polyoma virus, and JC virus. Its tumor antigen may be related to those of SV40 and BKV.
Topics: Animals; Antigens, Viral; DNA, Circular; DNA, Viral; Epitopes; Haplorhini; Kidney; Macaca; Molecular Weight; Papillomaviridae; Polyomaviridae; Polyomavirus; Simian virus 40
PubMed: 59705
DOI: 10.1128/iai.14.1.225-231.1976 -
Journal of Virology Aug 1982The integration of polyoma virus DNA into the genome of transformed rat cells generally takes place in a tandem head-to-tail arrangement. A functional viral large tumor...
The integration of polyoma virus DNA into the genome of transformed rat cells generally takes place in a tandem head-to-tail arrangement. A functional viral large tumor antigen (T-Ag) renders this structure unstable, as manifested by free DNA production and excision or amplification of the integrated viral DNA. All of these phenomena involve the mobilization of precise genomic "units," suggesting that they result from intramolecular homologous recombination events occurring in the repeated viral DNA sequences within the integrated structures. We studied polyoma ts-a-transformed rat cell lines, which produced large T-Ag but contained less than a single copy of integrated viral DNA. In all of these lines, reversion to a normal phenotype (indicative of excision) was extremely low and independent of the presence of a functional large T-Ag. The revertants were either phenotypic or had undergone variable rearrangements of the integrated sequences that seemed to involve flanking host DNA. In two of these cell lines (ts-a 4A and ts-a 3B), we could not detect any evidence of amplification even after 2 months of propagation under conditions permissive for large T-Ag. An amplification event was detected in a small subpopulation of the ts-a R5-1 line after 2 months of growth at 33 degrees C. This involved a DNA fragment of 5.1 kilobases, consisting of the left portion of the viral insertion and about 2.5 kilobases of adjacent host DNA sequences. None of these lines spontaneously produced free viral DNA, but after fusion with 3T3 mouse fibroblasts, R5-1 and 4A produced a low level of heterogeneous free DNA molecules, which contained both viral and flanking host DNA. In contrast, the ts-a 9 cell line, whose viral insertion consists of a partial tandem of approximately 1.2 viral genomes, underwent a high rate of excision or amplification when propagated at temperatures permissive for large T-Ag function. These results indicate that the high rate of excision and amplification of integrated viral genomes observed in polyoma-transformed rat cells requires the presence of regions of homology (i.e., repeats) in the integrated viral sequences. Therefore, these events occur via homologous intramolecular recombination, which is promoted directly or indirectly by the large viral T-Ag.
Topics: Animals; Antigens, Viral; Antigens, Viral, Tumor; Cell Line; Cell Transformation, Viral; DNA; DNA Restriction Enzymes; DNA, Viral; Gene Amplification; Mice; Polyomavirus; Recombination, Genetic; Repetitive Sequences, Nucleic Acid
PubMed: 6287035
DOI: 10.1128/JVI.43.2.617-628.1982 -
Proceedings of the National Academy of... Feb 1980Embryonal carcinoma (EC) mouse cells have been shown to be resistant to infection by retroviruses and small oncogenic DNA viruses, including simian virus 40 and polyoma....
Embryonal carcinoma (EC) mouse cells have been shown to be resistant to infection by retroviruses and small oncogenic DNA viruses, including simian virus 40 and polyoma. When allowed to differentiate, in vitro or in vivo, EC cells become as susceptible to these viruses as differentiated mouse cell lines are. In order to study the relationships between differentiation of EC cells and viral expression, we have isolated and characterized several polyoma mutants that can express early and late functions in undifferentiated EC cells. These mutants, which arose spontaneously during high-multiplicity infection of PCD3 cells (a differentiated fibroblast-like cell line derived from PCC3 EC cells), were selected on PCC4 cells (undifferentiated EC cells) and twice plaque purified. Restriction enzyme analysis of the DNA from several mutants has shown that they all exhibit an additional sequence located in the Pvu II endonuclease fragment 4, close to the junction between Hpa II endonuclease fragments 3 and 5. The size of the insertion varies from 10 to 50 base pairs. The biological properties, including oncogenicity, transforming ability, host range, and burst size of the mutants so far analyzed are similar to those of wild-type virus.
Topics: Base Sequence; Cell Line; DNA Restriction Enzymes; DNA, Viral; Mutation; Neoplasms, Experimental; Polyomavirus; Teratoma; Virus Replication
PubMed: 6244578
DOI: 10.1073/pnas.77.2.1068 -
The Journal of Experimental Medicine Jul 1959Treatment of guinea pig erythrocytes with types A and B influenza viruses rendered them inagglutinable by polyoma virus; also, the inhibitory effect of ovomucin on...
Treatment of guinea pig erythrocytes with types A and B influenza viruses rendered them inagglutinable by polyoma virus; also, the inhibitory effect of ovomucin on polyoma virus hemagglutination was destroyed by pretreatment of the ovomucin with various myxoviruses. These results indicate that polyoma virus and myxovirus erythrocyte receptor sites are identical. However, no destruction by polyoma virus of its own or of myxovirus receptors or inhibitors was detected. No serologic relationship was detected between polyoma virus and members of the myxovirus group; differences in size and stability further indicate their distinctness. No evidence was found of biologic or serologic relationship of polyoma virus with encephalomyocarditis virus or mouse encephalomyelitis virus.
Topics: Animals; Erythrocytes; Guinea Pigs; Hemagglutination; Mice; Mucoproteins; Orthomyxoviridae; Polyomavirus; Viruses
PubMed: 13664870
DOI: 10.1084/jem.110.1.81 -
Proceedings of the National Academy of... Apr 1963
Topics: DNA; DNA, Viral; Polyomavirus
PubMed: 13999555
DOI: 10.1073/pnas.49.4.480 -
Journal of Virology Feb 1974Secondary mouse embryo (ME) cultures which had been grown prior to infection in the presence of 5-bromodeoxyuridine (BUdR) and 5-fluorodeoxy-uridine were found to be...
Secondary mouse embryo (ME) cultures which had been grown prior to infection in the presence of 5-bromodeoxyuridine (BUdR) and 5-fluorodeoxy-uridine were found to be permissive for polyoma virus (16). The DNA extracted from the progeny virus yielded two bands on CsCl isopycnic centrifugation. The light band (LL) contained supercoiled circular (polyoma DNA I), open circular (polyoma DNA II), and linear (polyoma DNA III) molecules, as was seen by electron microscopy. The hybrid band (HL) contained exclusively linear molecules. This DNA was pure, density - labeled, pseudovirion DNA, i.e., fragmented HL mouse DNA. The quantitative comparison of HL and LL polyoma DNA III from six different virus preparations always revealed an excess of HL DNA, the ratio of HL/LL being between 1.2 and 2.2. These results led to the conclusion that in BUdR-prelabeled, polyoma-infected ME cells pseudovirion DNA is excised both from unreplicated and newly replicated regions of mouse DNA.
Topics: Animals; Bromodeoxyuridine; Cell Line; Cells, Cultured; Centrifugation, Density Gradient; Cesium; Chlorides; DNA; DNA Replication; DNA, Circular; DNA, Viral; Fibroblasts; Floxuridine; Mice; Microscopy, Electron; Polyomavirus; Tritium
PubMed: 4359295
DOI: 10.1128/JVI.13.2.285-290.1974 -
American Journal of Transplantation :... May 2006Polyomavirus-associated nephropathy is an important cause of dysfunction and failure of renal transplants. BK virus is an ubiquitous human polyoma virus that...
Polyomavirus-associated nephropathy is an important cause of dysfunction and failure of renal transplants. BK virus is an ubiquitous human polyoma virus that persistently infects the kidney. This otherwise silent infection can reactivate in immunosuppressed individuals, resulting in renal complications. Because polyoma viruses are highly species-specific, we developed a mouse polyoma virus-renal transplant model in order to investigate the pathogenesis of polyomavirus-associated nephropathy. Using this model, we found that polyoma virus preferentially replicates in the allogeneic kidney grafts, accelerating graft failure; thus, this animal model is able to mimic the polyomavirus-associated nephropathy seen in human renal transplant patients. Acute polyoma virus infection of mouse allograft recipients augmented the alloreactive CD8+ T-cell response, while maintaining the anti-viral CD8+ T-cell response. In addition to the known virus-induced cytopathology, these findings demonstrate a potential role for an enhanced anti-donor T-cell response in the pathogenesis of polyomavirus-associated nephropathy.
Topics: Animals; Base Sequence; CD8-Positive T-Lymphocytes; DNA Primers; Kidney Transplantation; Mice; Models, Animal; Nephrectomy; Polymerase Chain Reaction; Polyomavirus; Polyomavirus Infections; Postoperative Complications; Tumor Virus Infections; Viral Load; Viral Plaque Assay
PubMed: 16611327
DOI: 10.1111/j.1600-6143.2006.01265.x -
The EMBO Journal Mar 1986The distribution of two of the polyoma virus early proteins (the large and middle T-antigens) in lytically infected mouse cells and transformed rat cells has been...
The distribution of two of the polyoma virus early proteins (the large and middle T-antigens) in lytically infected mouse cells and transformed rat cells has been investigated by indirect immunofluorescence and immuno-electron microscopy using well-characterised monoclonal antibodies. By these techniques, the viral large T-antigen was found almost exclusively in the nucleus, sometimes in association with nuclear pores, but never in the nucleolus. In lytically infected, but not transformed cells, fluorescence was detected in discrete areas ('hot spots') within the nucleus and, in a minor population of lytically infected cells, cytoplasmic immunoreactive material was observed. The viral middle T-antigen was found in association with most cytoplasmic membranes and in the majority of cells mainly in the endoplasmic reticulum. Only a fraction of the staining was observed in the plasma membrane and no staining in the nucleoplasm was observed. The data suggest that the site of action of the major transforming activity of polyoma virus need not be at the plasma membrane. Functions associated with the viral antigens are discussed in terms of their subcellular distributions within cells.
Topics: Animals; Antibodies; Antigens, Polyomavirus Transforming; Antigens, Viral, Tumor; Cells, Cultured; Fluorescent Antibody Technique; Mice; Microscopy, Electron; Oncogene Proteins, Viral; Polyomavirus; Protein Kinases; Subcellular Fractions
PubMed: 3011409
DOI: 10.1002/j.1460-2075.1986.tb04238.x -
British Journal of Cancer Jan 1973Adult CBA mice thymectomized, treated with antilymphocytic globulin (ALG) and inoculated with human leprosy organisms were accidentally infected with polyoma virus and...
Adult CBA mice thymectomized, treated with antilymphocytic globulin (ALG) and inoculated with human leprosy organisms were accidentally infected with polyoma virus and all developed tumours. After cessation of ALG administration, some animals were given spleen cells from syngeneic donors immunized with polyoma virus; none developed tumours. Similar results were obtained in mice deliberately infected with polyoma virus but not with leprosy organisms. Passive transfer of antibody before but not after virus inoculation prevented tumour formation in immunosuppressed recipients. Virus infection in thymectomized, lethally irradiated and bone marrow reconstituted mice resulted in only a very low incidence of tumours. These results emphasize the role of immunological surveillance in preventing polyoma tumour formation under natural conditions.
Topics: Adenocarcinoma; Animals; Antibodies, Viral; Antilymphocyte Serum; Humans; Immunity, Maternally-Acquired; Immunization; Immunosuppression Therapy; Leprosy; Lung Neoplasms; Mammary Neoplasms, Experimental; Mice; Mice, Inbred CBA; Neoplasms, Experimental; Osteosarcoma; Polyomavirus; Sarcoma, Experimental; Spleen; Thymectomy
PubMed: 4346752
DOI: 10.1038/bjc.1973.2