Fig. (3) E1 represses UPR activation of CHOP. Huh-7 cells were co-transfected with the CHOP reporter gene plasmid and the respective plasmids as indicated together with the internal control plasmid encoding β-galactosidase for 32 h and then treated with 1 µg/ml of tunicamycin (Tm) or the dimethylsulphoxide (DMSO) solvent control for 16 h. The CHOP promoter luciferase activity was normalized against β-galactosidase activity and expressed relative to the solvent controls, which are set as 1. The values obtained represent the mean ± SEM of three independent experiments performed in triplicate. *Significance of the difference (P<0.05).