Fig. 2.

Stringency and compatibility evaluation of the MATE system. (A) Schematic illustration of the design of promoters in MATE-ON and MATE-OFF systems. (B) Construction of four different promoter mutants of the MATE-ON system harboring malO-OM15, cre-box mutation, or inserting the ON-type riboswitch LysRS59/TheoRS2. (C) Comparison of the fold induction ratio of the MATE-ON system with different promoter mutants using GFP as a reporter protein. The solid dot and empty dot indicate the fluorescence value that was detected with or without the inducer, respectively. (D) Compatibility of the maltose-activation and repression systems in one cell. Fluorescence reporter genes, E2-crimson and gfpmut2, were controlled by the maltose-activated promoter (MATE-ON) and maltose-repressible promoter (MATE-OFF) simultaneously in one expression vector. Plasmids with only the activated or repressed fluorescence reporter gene were transformed and used as positive controls for each system.