Submitted to: Virus Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/30/2010
Publication Date: 1/1/2011
Citation: Cheung, A.K., Greenlee, J.J. 2011. Identification of an amino acid domain encoded by the capsid gene of porcine circovirus type 2 that modulates intracellular viral protein distribution during replication. Virus Research. 155(1):358-362. Interpretive Summary: Porcine circovirus type 2 (PCV2) is a newly emerged viral pathogen of swine. While clinical signs of disease and postmortem lesions induced by PCV2 are known, there is little information on the temporal pathogenesis and epidemiology of the virus. In previous work, we showed that the 2005 porcine circovirus associated-disease outbreak was caused by a newly classified PCV2b virus and that there are genetic differences between the PCV2a and PCV2b viruses. In this work, we detected biological differences between these two subgroup viruses. The information obtained advances our understanding of circovirus biology and aids the research of scientists in industry, universities and government agencies.
Technical Abstract: Previous work showed that distinct amino acid motifs are encoded by the Rep, Cap and ORF3 genes of two subgroups of porcine circoviruses (PCV), PCV2a and PCV2b. At a specific location of the gene, a certain amino acid residue or sequence is preferred. Specifically, two amino acid domains located in the capsid protein, designated motif 1 (six residues located at positions 86 91) and motif 2 (four residues at positions 190 191 206 210), have been identified to associate with either PCV2a (motif-1a:TNKISI and motif-2a:SRKD) or PCV2b (motif-1b:SNPRSV and motif-2b:AGIE) preferentially. In this study, the protein distribution pattern of a PCV2a isolate and a PCV2b isolate was examined. Each virus exhibited a different viral protein pattern during replication in porcine kidney cells and the viral protein distribution pattern was associated with amino acid motif-2 but not motif-1. The results also showed that a more robust accumulation of viral proteins in the nucleus was associated with motif-2b than with motif-2a. In addition, viruses containing motif-2b replicated better than viruses containing motif-2a in porcine kidney cells.