VP16 forms the transcriptional regulatory complex via its conserved DNA binding domain, known as the VP16-induced complex formation domain (VIC), and the complex formed by VP16, HCF-1 and Oct-1 represents VP16-mediated activation of a viral gene cascade expression, which acts as a regulatory switch for two modes of viral infection, namely lytic infection and latent infection. The gene discussed is HCFC1; the disease is viral infectious disease.