Summary
By means of indirect immunofluorescence assay (IFA) using natural swine immune serum and hyperimmune serum from rabbits infected with porcine circovirus (PCV), a PCV antigen was detected present prior to the onset of viral and cellular DNA synthesis in nucleoli of cells of synchronized and growth stimulated infected PS cell cultures grown for more than 12 h in the presence of hydroxyurea. The number of cells containing specifically fluorescing nucleoli increased with increasing time of growth in the presence of hydroxyurea. The concomitant increase in the number of cells containing virus structural (VS) antigen in the nuclei and the increase in the amount of replicative (RF) DNA and accompanying 5 S DNA after release from the hydroxyurea block suggest that EA is involved in induction of PCV DNA replication. Primary pig kidney cell cultures persistently infected with PCV survived mock-infected control cultures for 16 passages. They had lost contact inhibition and formed cell colonies in soft agar at a ratio of 0.1 to 0.4%. Cell lines derived from agar colonies showed properties of transformed cells e.g. low requirement for serum growth factors, ability to overgrow a continuous cell layer, anchorage independence of growth. In transformed cells stimulated to growth and grown in the presence of hydroxyurea, non-structural viral antigen visible by IFA in nucleoli and VS antigen located in the cytoplasm were expressed. Contrary to virus bound nuclear VS antigen in productive infection, accumulation of cytoplasmatic VS antigen was independent of DNA synthesis and caused cell destruction, thus limiting growth of cell layers and colonies in soft agar.
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References
Angel P, Imagawa R, Chiu R, Stein B, Imbra RJ, Rahmsdorf HJ, Jonat C, Herrlich P, Karin M (1987) Phorbolester-inducible genes contain a common cis element recognized by a TPA-modulated trans-acting factor. Cell 49: 729–739
Angel P, Karin M (1991) The role of Jun, Fos and AP-1 complex in cell-proliferation and transformation. Biochim Biophys Acta 1072: 129–157
Curran T, Franza BR (1988) Fos and Jun: The AP-1 connection. Cell 55: 395–397
Dulac GC, Afshar A (1989) Porcine circovirus antigens in PK 15 cell lines (ATCC CCL-33) and evidence of antibodies to circovirus in Canadian pigs. Can J Vet Res 53: 431–433
Franza BR, Rauscher FJ, Josephs SF, Curran T (1988) The Fos complex and Fos-related antigens recognize sequence elements that contain AP-1 binding sites. Science 239: 1150–1153
Fuhrmann B, Buhk H-J, Tischer I (1990) Replication of porcine circo-virus depends on events in early G1 phase of infected cells. Abstracts VIIIth Int Congr Virol Berlin, p 381
Fuhrmann B (1992) Abhängigkeit der Replikation des Porcinen Circovirus von Prozessen in der frühen G1-Phase der infizierten Zelle. Dissertation, FU Berlin
Gelderblom HR, Hausmann EHS, Özel M, Pauli G, Koch MA (1987) Fine structure of human immunodeficiency virus (HIV) and immunolocalization of structural proteins. Virology 156: 171–176
Hess JL, Small JA, Clements JE (1989) Sequences in the visnavirus long terminal repeat that control transcription activity and respond to viral trans-activation: involvement of AP-1 sites in basal activity and trans-activation. J Virol 63: 3001–3015
Hirt B (1967) Selective extraction of polyoma DNA from infected mouse cell cultures. J Mol Biol 26: 365–369
Jeang K-T, Chiu R, Santos E, Kim SJ (1991) Induction of the HTLV-1 LTR by Jun occurs through the tax-responsive 21-bp elements. Virology 181: 218–227
Kubota S, Siomi H, Satoh T, Endo S, Maki M, Hatanaka M (1989) Functional similarity of HIV-1 rev and HTLV-I rex proteins: identification of a new nucleolar-targeting signal in rev protein. Biochim Biophys Res Commun 162: 963–970
Kubota S, Furuta R, Maki M, Hatanaka M (1992) Inhibition of human immunodeficiency virus type I Rev function by a Rev mutant which interferes with nuclear/nucleolar localization of Rev. J Virol 66: 2510–2513
Lee W, Haslinger A, Karin M, Tjian R (1989) Activation of transcription by two factors that bind promoter and enhancer sequences of the human metallothionein gene and SV 40. Nature 325: 368–372
Ley KD, Tobey RA (1970) Regulation of initiation of DNA synthesis in Chinese hamster cells. II. Induction of DNA synthesis and cell division by isoleucine and glutamine in G1-arrested cells in suspension culture. J Cell Biol 47: 453–459
Macpherson I, Montagnier L (1964) Agar suspension culture for the selective assay of cells transformed by polyoma virus. Virology 23: 291–294
Macpherson I (1969) Agar suspension culture for quantitation of transformed cells. In: Habel K, Salzman NP (eds) Fundamental techniques in virology Academic Press, New York London, pp 214–219
Mankertz J (1990) Untersuchungen von Transkriptionseinheiten des Porcinen Circovirus (PCV). Dissertation, FU Berlin
Martin ME, Piette J, Yaniv M, Tang W-J, Folk WR (1988) Activation of the polyomavirus enhancer by a murine activator protein 1 (AP1) homolog and two contiguous proteins. Proc Natl Acad Sci USA 85: 5839–5843
Moennig V, Frank H, Hunsmann G, Ohms P, Schwarz H, Schäfer W, Strandström H (1974) C-type particles produced by a permanent cell line from a leukemic pig II. Physical chemical and serological characterization of the particles. Virology 57: 179–188
Monier R (1987) Transformation by SV 40 and polyoma. In: Salzman NP (ed) The papovaviridae, vol 1. Plenum Press, New York London, pp 247–294
Niedrig M, Rabanus JP, L'age-Stehr J, Gelderblom H, Pauli G (1988) Monoclonal antibodies directed against human immunodeficiency virus (HIV) gag proteins with specificity for conserved epitopes in HIV-1, HIV-2 and simian immunodeficiency virus. J Gen Virol 69: 2109–2114
Nosaka T, Siomi H, Adachi Y, Ishibashi M, Kubota S (1989) Nucleolar targeting signal of human T-cell leukemia virus type I rex-encoded protein is essential for cytoplasmic accumulation of unspliced viral mRNA. Proc Natl Acad Sci USA 86: 9798–9802
Tischer I, Gelderblom H, Vettermann W, Koch MA (1982) A very small porcine virus with circular single-stranded DNA. Nature 295: 64–66
Tischer I, Mields W, Wolff D, Vagt M, Griem W (1986) Studies on epidemiology and pathogenicity of porcine circovirus. Arch Virol 91: 271–276
Tischer I, Peters D, Rasch R, Pociuli S (1987) Replication of porcine circovirus: induction by glucosamine and cell cycle dependence. Arch Virol 96: 39–57
Tischer I, Buhk H-J (1988) Viral DNA from cells infected with porcine circovirus. Zentralbl Bakt Hyg A 270: 280–287
Tischer I, Bode L, Peters D, Pociuli S, Germann B (1995) Distribution of antibodies to porcine circovirus in swine populations of different breeding farms. Arch Virol 140: 737–743
Tischer I, Bode L, Apodaca J, Timm H, Peters D, Rasch R, Pociuli S, Gericke E (1995) Presence of antibodies reacting with porcine circovirus in sera of humans, mice and cattle. Arch Virol 140: 1427–1439
Yoshiike K, Takemoto KK (1987) Studies with BK virus and monkey lymphotropic papovavirus. In: Salzman NP (ed) The papovaviridae, vol 1. Plenum Press, New York London, pp 295–326
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Tischer, I., Peters, D. & Pociuli, S. Occurrence and role of an early antigen and evidence for transforming ability of porcine circovirus. Archives of Virology 140, 1799–1816 (1995). https://doi.org/10.1007/BF01384343
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DOI: https://doi.org/10.1007/BF01384343