Cloning and sequencing of complete genome of porcine circovirus type 2 (PCV-2) YU A strain
The replicative genomic DNA of porcine circovirus type 2 (PCV-2) of YU A strain was extracted from the infected PK-15 cells. The complete genome of YU A strain was amplified by utilizing an inverse PCR approach with one pair of special primers. A 1.76kb fragment was obtained and cloned into pMD-18T vector resulting the recombinant plasmid T-PCV-2 that contained the complete genomic DNA of YU A strain. The sequence analysis showed that YU A strain genome consisted of 1767nt, which shares 97% sequence identity with other PCV-2 strains in GenBank. We also found replicative genome of YU A strain contained ten open reading frames (ORFs). The major ORFs were ORF1 and ORF2, that encoded 314 and 234 amino acids respectively. Amino acid sequence homology of ORF1 and ORF2 between YU A strain and PCV-1 were 85% 66% respectively. The ORF1 of YU A strain displayed 98%-99% identity based on amino acids with other PCV-2 strains, but 92%-97% in ORF2.