siRNA knockdown.

siRNA for SV40 LTag, 5′-AAAATTGTGTACCTTTAGCTT-3′ (63), and a scramble control siRNA were synthesized (Eurogentec S.A, Belgium). To determine the effects of siRNA transfection, 1.5 × 10⁵ HEK293T cells were seeded in 12-well plates and transfected 24 h postseeding with 30 nM siRNAs using Lipofectamine 2000 according to the manufacturer's instructions. After 24, 48, and 72 hpt, cells were harvested for SV40 LTag and sTag immunoblotting. To analyze the effect of LTag knockdown on reporter expression, reporter plasmids were transfected at 24 h post-siRNA transfection.