Figure 2.

Transient transfection analysis of the new Ptet promoters in HeLa-EM2 cells. Left panel: Firefly luciferase activities after transfection of HeLa-EM2 cells with the new Ptet promoter driven reporter constructs were determined in the on-(+Dox) and off-state (-Dox) of the system. Values were normalized to the activity of a cotransfected internal standard (beta-galactosidase reporter). Statistical comparison of Ptet-1 and Ptet-14 with Ptet-T6 via students t-test was performed with Graph Pad Prism version 5.03 software (** = p-value < 0,01, *** = p-value < 0.001, n.s. = not significant). High amounts of luciferase reporter plasmids were transfected to achieve relative light unit readings above instrument background that could be reliably quantified. For example, in this experiment the instrument background (identical to mock transfected cells) was 1,5 × 10² rlu while that of extracts from Ptet-T6 transfected cells (-Dox) was 3,5 × 10² rlu. Right panel: Regulation factors for the individual Ptet promoters from the analysis shown left. The results shown are the mean of three independent transfection experiments, the error bars represent the SEM.