猪圆环病毒3型（PCV3）是影响我国养猪业的重要病原之一，目前尚无商品化疫苗用于防控该病。Cap蛋白是PCV3主要的抗原蛋白。为构建高水平表达可溶性PCV3 Cap蛋白的工程菌株，对Cap蛋白NLS序列进行定点突变，构建重组表达载体pPICZαA-PCV3，经转染、酵母细胞表达以及纯化，最终获得可溶性PCV3 Cap蛋白。随后对纯化蛋白进行Western Blot验证及电镜观察。结果显示：获得的PCV Cap蛋白大小约27 kDa；电镜下观察可见均一的病毒样颗粒（VLP），颗粒直径约18 nm。PCV3 Cap蛋白在酵母细胞中的成功表达为进一步开发Cap蛋白亚单位疫苗奠定了基础。
Porcine circovirus type 3（PCV3）is one of the most serious pathogens that would affect pig industry in China，but no commercial vaccine has been available till now. In order to establish an engineered strain that could express soluble PCV3 Cap protein at a high level，considering that Cap protein was the main antigenic protein of PCV3. The nuclear localization sequence（NLS）of Cap protein was specifically mutated to establish the recombinant plasmid pPICZαA-PCV3，after transfection of the plasmid as well as expression and purification of recombinant protein，the soluble PCV3 Cap protein was obtained. Then the purified protein was verified by Western Blot and observed under electron microscope. It was concluded that the PCV Cap protein obtained was about 27 kDa，and uniform virus-like particles（VLP）with the diameter of 18 nm were observed under electron microscope. The successful expression of PCV3 Cap protein in yeast cells laid a foundation for further development of Cap protein subunit vaccines.