promoter /-mō″tər/ [L, promovere, to move forward] , 1. a DNA sequence that initiates transcription of the genetic code. 2. a cocarcinogen that encourages cells altered by initiators to reproduce more rapidly than normal, increasing the probability of malignant transformation. Examples include chlorophenothane (DDT), phenobarbital, saccharin, sunlight, and some chemicals in cigarette smoke. The effects of promoters are sometimes reversible.
