Figure 3.

Protein–protein interaction between BcWCL1 and BcWCL2 is mediated mainly by PAS domains. Different variants of the BcWCL1 protein were assayed for protein–protein interaction with the full length BcWCL2 or BcWCL2 without the PAS domain. Luciferase expression was measured as luminescence in arbitrary units (a.u.) of the yeast cell cultures. The protein–protein interaction activates luciferase expression controlled by the 5XGAL1 synthetic promoter (P_5XGAL1) under three different experimental conditions: (A,D) constant darkness (DD), (B,E) constant blue light (BL), and (C,F) a single blue-light pulse of 2 h duration (between dotted lines). The FUN-LOV optogenetic switch [32] was used as positive control of light-mediated protein–protein interaction that activates luciferase expression. In panels (D–F), the zoom shows the luciferase expression at lower scale. In all panels, the average of six biological replicates is shown, with standard deviation represented as shadowed grey regions.