Cloning and sequence analysis of complete genome and ORF2 gene of porcine circovirus (PCV) type 2

Refer to the complete gene sequences of PCV2 published in GenBank,a pair of special primers was designed by reverse PCR method and the complete gene sequence of isolated strain GX-FSH of PCV2 was amplified by PCR.In addition,another pair of primers was used to amplify the complete sequence of ORF2.Then these PCR products were cloned into the pMD 18-T vector,respectively,and the recombined positive plasmids were obtained.The sequences of the cloned PCR products were analyzed and compared to other PCV2 isolations in GenBank,the results indicated that the homology of their nucleotide complete sequence was 94.6%-99.4% and the homology of the related ORF gene was 90.0%-99.1% and that of deduced amino acid was 90.1%-98.7%.Finally,the protein structure of ORF2 was predicted and analyzed by biological software,and it suggested that the secondary structure of mature protein of ORF2 belonged to the β-structure.