RNA Polymerase is a complex enzyme composed of multiple subunits. In prokaryotes, the enzyme consists of a core enzyme and a sigma factor, which is essential for the initiation of transcription. In eukaryotes, there are three main types of RNA Polymerase (I, II, and III), each responsible for transcribing different classes of genes. The eukaryotic RNA Polymerases have additional subunits and require various transcription factors for regulation.
