LMP1-induced RON expression plays a critical role in the proliferation of LCLs. (A) LCL-1 (left panel) and LCL-2 (right panel) cells were electroporated with control siRNA or RON siRNA plasmids. Before the indicated time point, 1 μCi [³H]-thymidine was added and incubation continued for another 18 hours. The amount of incorporated [³H]-thymidine was measured using a β-counter. (B) LCL-1 cells were electroporated with control siRNA or LMP1 siRNA plasmids for 3 days and then transfected with RON expression plasmids for another 3 days. The amount of incorporated [³H]-thymidine was measured using a β-counter (left panel). The total proteins were harvested and the expression of RON, LMP1 and GAPDH was detected by Western blotting (right panel). *P < .05 by Student t test.