Figure 2.

L1 siRNA specifically inhibits the expression of a hybrid luciferase transcript driven by the L1 5′-UTR internal promoter. HCT116 cells were co-transfected with the indicated firefly (FF) luciferase expression vector and increasing amounts of L1 siRNA or control siRNA. Relative FF luciferase activity in the absence of siRNA was set at 1.0. The amount of each specific siRNA is indicated below the graphs. (A) Luciferase assays performed with in vitro ‘diced’ siRNA. Diced LacZ siRNA and synthetic FF luciferase siRNA served as negative and positive controls, respectively. (B) Luciferase assays performed with synthetic siRNA targeting nucleotides 749–769 of the L1 5′-UTR. Irrelevant synthetic siRNA targeting the HIV Rev transcript was included as the negative control.