Sequence Analysis of ORF2 Gene of Type 2 Porcine Circovirus and Construction of Eukaryotic Expressing Vector of ORF2

Abstract：According to the published ORF2 gene sequence of PCV一2，two primers were designed．and ORF2 gene was amplified from suspected PMW S sample using PCR．Then the PCR product was cloned into pGEM ．T easy vector，and recombinant plasmid nam ed pTORF2 was obtained The cloned ORF2 gene in pTORF2 was sequenced and compared with other PCV isolates in GenBank，the results demonstrated that the ORF2 gene is closely related with a USA isolate AF264039．the homology of their nucleotide and amino acid sequence both were 100％ ． In addition． there existed 92．3％ to 98．6％ nucleotide sequence identity and 92．3％ to 96 6％ amino acid sequence identity with other PCV-2 isolates．Recombinant plasmid pTORF2 was digested with Bam H I／EcoR V．ORF2 gene Was purified．and introduced into eukaryotic expressing veCtor pSecTag2／HygroB between BarnH I and E∞R V enzyme site．then pSecTagORF2 recom binant plasmid was constructed ．Further research is underway to study the biological activity of ORF2 protein and establish the diagnostic kit of PCV．