Fig. 3. Effects of FUSn insertion into OptoTF constructs on gene expression levels.

(A) Effect of the IDR integration site. FUSn was integrated into OptoTF- either between eYFP and VP16 or at the N terminus of Cry2. The constructs were cotransfected into HEK-293 cells together with a tetO₇-based SEAP reporter and CIBn-TetR. Cells were cultivated in the dark or under blue light (465 nm, 5 μmol m⁻² s⁻¹) for 48 hours before quantifying SEAP production. (B) Gene expression mediated by OptoTF constructs. The experiment was performed as described in (A) except that reporters with different numbers of tetO repeats (1 to 6, 26) were used. The model fit to the data is represented by the curves, while the shaded error bands are estimated with an error model with a constant and relative Gaussian error. (C) OptoTF-mediated expression kinetics. OptoTF + FUS and OptoTF- were cotransfected together with a tetO₄-based SEAP reporter and CIBn-TetR. Cells were cultivated in the dark or under blue light, and SEAP production was quantified at the indicated time points. The model fit to the data is represented by the curves, while the shaded error bands are estimated with an error model with a constant and relative Gaussian error.