There is a theoretical protein called largeX that helps to stimulate growth of the body during adolescence. The promoter on the lrgX gene that codes for it is normally able to have a protein bind to it that promotes transcription called largene. Largene, bound to the promoter, can receive yet another signal in the form of largeXase—a protein that changes the conformation of largene so that it can no longer bind to the promoter. It would be accurate to describe the lrgX operon as both positive and repressible
negative and repressible
positive and inducible
negative and inducible