Abstract: This study was aimed to express viral protein genome-linked (VPg) of porcine sapovirus, using the RNA of the CH430 strain of Northwestern China as a template, the VPg gene was amplified by RT-PCR and cloned into pMD19-T Simple Vector, and then recombinant plasmid was confirmed by double-endonuclease digestion and DNA sequencing. VPg gene was subcloned into a prokaryotic expression vector pET-30a to obtain the prokaryotically expressed plasmid pET30a-VPg. The positive recombinant plasmid was transformed into E. coli BL21 (DE3) cells to induce expression. The fusion purified protein was injected into rabbits to produce hyper-immune serum, the specificity and titer of the hyper-immune serum were determined by Western blotting and ELISA. The results indicated that the full-length of VPg gene was 339 bp, encoding 113 amino acids. The expression of recombination protein reached a maximum level when the recombinant bacteria at the condition of 37 ℃, final concentration of IPTG at 1.0mmol/L and the time of induction at 6 h. The purpose protein at size of 22 ku was consistent with expectation and expressed in the form of inclusion bodies analyzed by SDS-PAGE. Western blotting exhibited that expression products had good reactogenicity with the hyper-immune serum. ELISA result showed hyper-immune serum titer was 1:12 800 and had good specificity. The hyper-immune serum laid the foundation for further investigation on the structure and function of non-structural protein VPg of porcine sapovirus.

Key words: porcine sapovirus; viral protein genome-linked (VPg); prokaryotic expression; purification