Ectopic expression of TIM enables dPER(ΔCBD) to inhibit dCLK-dependent transcriptional activity in S2 cells. (A) S2 cells were transiently transfected in the presence (+) or absence (-) of pMT-dClk-V5. In addition, 20ng of pAct-dper (WT) or pAct- dperΔCBD (ΔCBD) were transfected either singly or in combination with increasing amount of pAct-tim (20, 50, 100ng). Luc activity in the absence of transfecting pMT-dClk-V5 was set to 1, and all other values were normalized. (B) S2 cells were transiently transfected with pMT-dClk-V5 in combination with increasing amount of pAct-dper (WT), pAct-dper-NLS (WT-NLS), pAct-dper ΔCBD (ΔCBD), or pAct-dper ΔCBD-NLS (ΔCBD-NLS). Luc activity in the absence of any dper-containing plasmid were set to 100% and all other values normalized. Shown are the average values from three independent experiments for relative luciferase activity(error bars denote S.E.M.).