Figure 7
mRNA and protein expression kinetics after nitrate-induction of the nitA promoter. Transformant NitLuc-A172 expressing the g-luc reporter gene under control of the nitA promoter was induced by a switch from NH4 + to NO3 − medium at 0 min. Both the g-luc mRNA and the luciferase activity were investigated at several time points after induction. The relative g-luc mRNA level was calculated in comparison to the reference gene tbpA using the 2-ΔCt method for analysis of the real-time RT-PCR results. The protein expression was determined with luciferase activity assays using the chlorophyll concentration of each sample for normalization.