# Terminator --- >Come with me if you want to live. >~ The Terminator **Terminators** are sections of [[DNA]] following a gene that signals for the [[RNA polymerase]] to finish [[transcription|transcribing]] a particular gene. The way it works is a two step process: making a hairpin loop in the RNA and then popping it off with a series of weak bonds. (There are actually different mechinisms out there for terminators, but we will focus on this one.) ![[terminator.png]] ## Step 1: The Hairpin Loop The terminator region codes for a portion of [[palindromic sequence|self-complementary]] [[mRNA]]. This causes the mRNA to actually form hydrogen bonds with itself in a "hairpin loop" shape. This can snag up the [[RNA polymerase]], physically stopping it. ## Step 2: AAAAA Once the hairpin loop has been formed there are a series of As in the coding strand. These are of course [[complementary base pairing|complementary pairs]] with Us in RNA, which creats a series of A–U bonds. These have the property of being relatively weak bonds, so, with the combination of the hairpin loop jamming up the works, the [[RNA polymerase]] just pops off the DNA. ___