UBE3A and coinfection: The E6AP levels were further downregulated when HBx and HCV core protein were expressed together by transient transfection in HepG2 cells (Fig. 3I, lane 3) and HBV/HCV coinfection established by either the transient transfection of a 1.2-mer HBV replicon in Huh7D cells (Fig. 3J, lane 4) or infection with HBV in Huh7D-NTCP cells (Fig. 3K, lane 4), resulting in a dramatic decrease in the ubiquitination of the HCV core protein and the subsequent upregulation of the intact HCV core protein in the presence of HBx (Fig. 3D to G, lanes 3).