TAT and coinfection: Further, Tat-triggered differential expression of these genes in the presence (APC140) and absence (Huh7.5.1) of HCV viral proteins was dramatic, especially for GNMT and IFI27, substantiating the significance of co-operative action between HIV-1 and HCV viral proteins in regulating the cellular genes in the co-infection-mediated pathobiology of hepatocytes.