Figure 4.

Induction of LMP1 expression activates p27^Kip1 expression. Ramos cells were stably transfected with an expression vector (MT-LMP1) in which LMP1 expression was dependent on the metallothionein promoter, or with empty control vector (MT). The stably transfected cells were treated with CdCl₂ for 16 hours or 24 hours as indicated, and then LMP1 expression (top), p27^Kip1 expression (middle), and β-actin expression (bottom, as a loading control) were analyzed by Western immunoblotting using specific antibodies. The results show that p27^Kip1 is induced on LMP1 induction. A modest p27^Kip1 induction is observed also in control cells because of CdCl₂ treatment.