Submitted to: International Congress of Virology
Publication Type: Abstract Only
Publication Acceptance Date: July 27, 2002
Publication Date: July 27, 2002
Technical Abstract: Porcine circovirus is a nonenveloped, icosahedral virus of 17 nm in diameter. It contains a single-stranded, covalently closed, circular DNA genome. PCV type 1 (PCV1) is non-pathogenic while PCV type 2 (PCV2) is associated with postweaning multisystemic wasting syndrome (PMWS) in swine. In this study, experiments were conducted to examine the biosynthesis of progeny virus PCV2 replication in a PCV-free porcine kidney cell line. At various times postinfection (p.i.), PCV2-infected PK15 cells were assayed for progeny viruses, viral RNAs, and viral proteins. During productive infection, viral antigens, RNAs, and progeny viruses all increased in a time dependent manner. The results showed that viral antigens and cell-free progeny viruses began to appear at 18 h and 30 h p.i., respectively. Virus-specific RNAs [950, 750, and 450 nucleotides (nt)] were detected by Northern blot analysis starting at 18 h p.i. The 950 nt species was the most prominent and it codes for the viral capsid protein. The 750 and 450 nt RNAs were derived from the Rep gene region. These two RNAs share 3' common nucleotide sequences and they are transcribed in the same orientation as the proposed unspliced Rep RNA or the Rep'RNA of PCV1. By polymerase chain reaction (PCR) assay, the unspliced Rep RNA was also detected. A fine map of the PCV-specific transcripts will be presented.