TP53 and viral infectious disease: In addition, the open reading frame 3 (ORF3) protein of porcine circovirus type 2 (PCV2) could bind to PIRH2 and suppress PIRH2-mediated p53 ubiquitination, resulting in the accumulation of p53 during viral infection, and the ORF3-induced apoptosis plays a major role in PCV2 pathogenesis (45).