PCV2 expresses three major proteins, the replicase Rep, the capsid protein Cap, and the non-structure protein ORF3 during infection, to figure out which component plays a predominant role in the enhancement of pNPM1 SUMOylation, PK-15 cells were infected with the same doses of recombinant adenovirus expressing PCV2 Rep (rAd-Rep), PCV2 Cap (rAd-Cap), and PCV2 ORF3 (rAd-ORF3), as well as blank recombinant adenovirus (rAd-blank), respectively. The gene discussed is ASZ1; the disease is infection.