Figure 4

C-terminal truncations lead to the decreased half-life and transactivation activity of HBx. (A) HepG2 cells in six-wells plates at 80% confluenc were transfected with 0.5 μg HA 154 HBx, 1 μg HA 1–140 HBx and 3 μg HA 1–119 HBx constructs. After 24 h transfection, cycloheximide (CHX, 30 μg ml⁻¹) was added to the medium to inhibit protein synthesis, and then the HBx protein was monitored by western blotting with an anti-HA antibody at the indicated time points. (B) The schematic illustration shows the densitometric quantification of the results in which the expression of HA 154 HBx, HA 1–140 HBx, or HA 1–119 HBx at time zero was set as 100%. The expression levels of these mutants at subsequent time points are expressed as a percentage of the levels of each relative to their expression at time zero. The error bars represent s.e. (C) HepG2 cells were cotransfected with the luciferase reporter gene constructs, pBI-GL-V6L, and an array of amounts of the indicated HBx plasmids. After 24 h transfection, the activity was detected by luciferase assays. The error bars represent s.e. (D) The protein levels of HBx of these samples were detected via western blotting analysis with an anti-HA antibody. The experiments were repeated three times with similar results.