RNA polymerase II

The review is devoted to the major features of RNA polymerase II, an enzyme responsible for transcription of the genes encoding all eukaryotic proteins. The structure of this enzyme is characterized by the presence of a domain comprising a tandem of heptapeptides each containing five hydroxyl groups undergoing phosphorylation-dephosphorylation during enzyme action, specifically upon transition from the transcription initiation stage to the elongation stage. Also considered are the roles of the main transcription factors in the interaction of the enzyme with a promoter and its opening, as well as the contribution of ATP to this process. The connection between transcription and pre-mRNA processing (splicing, capping at the 5'end and polyadenylation at the 3'end) as well as that between DNA transcription and repair are documented. As the targets for eukaryotic RNA polymerases are nucleosomes, not free DNA, the transition of chromatin into the transcription-competent form is also touched upon.