Cloning and sequencing analysis of ORF2 gene of porcine circovirus type 1

The ORF2 gene was amplified from PK-15 cells and tissues of piglets suffered from PMWS,respectively using the primers designed according to the OFR2 sequences published in GenBank.The resultant PCR products were cloned into pMD18-T vectors and identified by restriction digestion using endonucleases XhoⅠ and KpnⅠ.Nucleotide sequences of the PCV1 ORF2 genes were compared with that of other PCV1 ORF2 and PCV2 ORF2 genes.The results indicated that nucleotide homology between ORF2 genes cloned from PK-15 cells and pig tissues was 99.4%,nucleotide homologies between the cloned PCV ORF2 genes and the published PCV1 ORF2 genes in GenBank were from 97.3% to 99.9%,and homologies between the cloned PCV ORF2 genes and the published PCV2 ORF2 genes in GenBank were from 67.9% to 68.4%.Several conserved functional domains were identified in the cloned PCV1 ORF2 genes.Predication of antigenicity showed that the protein translated by the PCV1 ORF2 genes may have good immunogenicity.