Crystal structures of the complete 12-subunit RNA polymerase II and its subcomplex Rpb4/7, and modeling of RNA polymerases I and III

RNA polymerase II (Pol II) is the central enzyme, that synthetizes
all mRNA in eukaryotic cells. In this work, I solved the structure
of the complete, initiation-competent 12-subunit yeast RNA
polymerase II at 3.8 Å. I also solved the structure of the Pol II
subcomplex of Rpb4/7 alone at 2.3 Å resolution. These structures
reveal the details of Pol II assembly from 12 subunits and give
important insights into the initiation of transcription. The
refined, atomic model of the complete 12-subunit Pol II enabled
homology modeling of the two other nuclear RNA polymerases. In Pol
I and Pol III, 65 % and 77 % of the Pol II fold are conserved,
respectively. Together with a recent structure of a Pol II
elongation complex, these results show that the basic mechanism of
transcription applies also to the two other nuclear RNA polymerases