The trp operon contains five genes: trpE, trpD, trpC, trpB, and trpA. These five genes code for components that produce three enzymes that catalyze the biosynthesis of tryptophan. The trpL region is the leader region, which helps regulate transcription once RNA polymerase has initiated transcription. This section of d n a contains the trp operon region, which includes in order, P , and the trp genes L, E, D, C, B, and A. The trp operon also undergoes negative regulation by a repressor. Tryptophan is the signal molecule (effector molecule) that binds to the repressor. Determine which events lead to an increase in transcription.