However, a phenomenon that is well worthy of our attention during PCV2 infection, since the host protein MKRN1 (a Cap interacting protein) mediates the degradation of Cap that limits the Cap protein levels at the early phase of infection, our results also showed that the Cap expression levels were not increased during PCV2 infection within 24 h in this study, which is similar as the results presented in our previous study [16]. The gene discussed is MKRN1; the disease is infection.