a. proTeOn behavior. In the absence of aTc, rTetR does not bind tetO and PROTEON does not upregulate gfp. Upon activation with aTc, rTetR binds the inducer, undergoes a conformational change and binds tetO, bringing LuxRΔN near its operator site to bind luxbox and upregulate gfp transcription through RNApol recruitment to the promoter.
b. proTeOn logic. In the absence of aTc, PROTEON does not control GFP expression. Upon induction with aTc, PROTEON upregulates GFP.
c. proTeOff behavior. In the absence of aTc, TetR binds to tetO, bringing LuxRΔN near its operator site to bind luxbox and upregulate gfp transcription through RNApol recruitment. After the addition of aTc, TetR binds to the small molecule, undergoes a conformational change, and releases tetO. Upon dissociation of TetR:tetO, the LuxRΔN:luxbox interaction is destabilized and upregulation by RNApol recruitment terminated.
d. proTeOff logic. In the absence of aTc, PROTEOFF upregulates GFP expression. Upon the addition of aTc, PROTEOFF’s control on GFP expression is terminated.