How does RNA polymerase work?

RNA polymerase is a large enzyme with multiple subunits. It is the main enzyme responsible for transcribing DNA into RNA. During transcription, RNA polymerase unzips a double DNA strand and uses one of the strands as a template for building a new RNA molecule through base pairing. It does this in three distinct steps – initiation, elongation and termination.

In the initiation step, RNA polymerase wraps around the promoter region of DNA. It proceeds to the second stage of elongation after successfully binding DNA at the targeted promoter region.

During the second step of elongation, RNA polymerase unzips DNA into two single strands and uses one as a genetic template for RNA synthesis.

Termination, which is the last step, is initiated when RNA polymerase encounters a terminator sequence or signal. When this happens, RNA polymerase stops adding complementary nucleotides to the RNA strand and releases the completed RNA transcript.