Cloning,sequence analysis and prokaryotic expression of ORF2 gene of PCV-2 Shaanxi strain

[Objective] PCV-2 SX strain ORF2 gene was cloned,analyzed and expressed in E.coli.[Method] According to the published complete nucleotide sequence of PCV-2 in GenBank,a pair of primers specific to the full-length of ORF2 gene were designed.The ORF2 gene fragment amplified by PCR was cloned into pGEM-T vector.The recombinant plasmid was sequenced and ORF2 gene was compared with other Genebank's PCV-2 strains.ORF2 gene segment was amplified from recombinant plasmid by PCR,then the ORF2 gene was cloned into vector pET-32a for prokaryotic expression in E.coli.[Result] The ORF2 gene of Shaanxi strain was 702 bp in full-length.It shared higher nucleotide and amino acid sequences homology with different strains of our country and foreign countries.The recombinant fusion proteins were highly expressed in E.coli BL21 in the form of soluble protein.The molecular weight of the expressed fusion protein was approximately 28 ku.Western-blot showed that the recombinant protein can be recognized by PCV-2 positive serum.[Conclusion] PCV-2 Shaanxi strain ORF2 gene was cloned and expressed in E.coli successfully.