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).