Structure of the initiation-competent RNA polymerase I and its implication for transcription.
Fiche publication
Date publication
juillet 2016
Journal
Nature communications
Auteurs
Membres identifiés du Cancéropôle Est :
Dr SCHULTZ Patrick
Tous les auteurs :
Pilsl M, Crucifix C, Papai G, Krupp F, Steinbauer R, Griesenbeck J, Milkereit P, Tschochner H, Schultz P
Lien Pubmed
Résumé
Eukaryotic RNA polymerase I (Pol I) is specialized in rRNA gene transcription synthesizing up to 60% of cellular RNA. High level rRNA production relies on efficient binding of initiation factors to the rRNA gene promoter and recruitment of Pol I complexes containing initiation factor Rrn3. Here, we determine the cryo-EM structure of the Pol I-Rrn3 complex at 7.5 Å resolution, and compare it with Rrn3-free monomeric and dimeric Pol I. We observe that Rrn3 contacts the Pol I A43/A14 stalk and subunits A190 and AC40, that association re-organizes the Rrn3 interaction interface, thereby preventing Pol I dimerization; and Rrn3-bound and monomeric Pol I differ from the dimeric enzyme in cleft opening, and localization of the A12.2 C-terminus in the active centre. Our findings thus support a dual role for Rrn3 in transcription initiation to stabilize a monomeric initiation competent Pol I and to drive pre-initiation complex formation.
Référence
Nat Commun. 2016 Jul;7:12126