The construction of an expressed plasmid used for detecting subcellular localization was described below. The full-length of CAV VP1 was amplified by PCR using the specific primer sets wt-VP1-f: 5’-CCCGAATTCATGGCAAGACGAGCTCGC-3′, wt-VP1-r: 5’-CGCGTCGACTCAGGGCTGCGTCCCCCAGTA-3′ from the CAV VP1 template that was kindly provided by Dr. Yi-Yang Lien. The PCR product was then cloned into expression vector pEGFP-C2 (#6083–1, Clontech, USA) between EcoR I and Sal I sites to generate a recombinant plasmid named pEGFP-VP1.