title: Structure of the initiation-competent RNA polymerase I and its implication for transcription.
abstract: 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.
authors.affiliation: Universität Regensburg, Biochemie-Zentrum Regensburg (BZR), Institut für Biochemie, Genetik und Mikrobiologie, Lehrstuhl Biochemie III, 93053 Regensburg, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Pilsl
authors.affiliation: Department of Integrated Structural Biology, IGBMC (Institut de Génétique et de Biologie Moléculaire et Cellulaire) INSERM, U964; CNRS/Strasbourg University, UMR7104 1, rue Laurent Fries, BP10142, 67404 Illkirch, France.
authors.forename: Corinne
authors.initials: C
authors.lastname: Crucifix
authors.affiliation: Department of Integrated Structural Biology, IGBMC (Institut de Génétique et de Biologie Moléculaire et Cellulaire) INSERM, U964; CNRS/Strasbourg University, UMR7104 1, rue Laurent Fries, BP10142, 67404 Illkirch, France.
authors.forename: Gabor
authors.initials: G
authors.lastname: Papai
authors.affiliation: Department of Integrated Structural Biology, IGBMC (Institut de Génétique et de Biologie Moléculaire et Cellulaire) INSERM, U964; CNRS/Strasbourg University, UMR7104 1, rue Laurent Fries, BP10142, 67404 Illkirch, France.
authors.forename: Ferdinand
authors.initials: F
authors.lastname: Krupp
authors.affiliation: Universität Regensburg, Biochemie-Zentrum Regensburg (BZR), Institut für Biochemie, Genetik und Mikrobiologie, Lehrstuhl Biochemie III, 93053 Regensburg, Germany.
authors.forename: Robert
authors.initials: R
authors.lastname: Steinbauer
authors.affiliation: Universität Regensburg, Biochemie-Zentrum Regensburg (BZR), Institut für Biochemie, Genetik und Mikrobiologie, Lehrstuhl Biochemie III, 93053 Regensburg, Germany.
authors.forename: Joachim
authors.initials: J
authors.lastname: Griesenbeck
authors.affiliation: Universität Regensburg, Biochemie-Zentrum Regensburg (BZR), Institut für Biochemie, Genetik und Mikrobiologie, Lehrstuhl Biochemie III, 93053 Regensburg, Germany.
authors.forename: Philipp
authors.initials: P
authors.lastname: Milkereit
authors.affiliation: Universität Regensburg, Biochemie-Zentrum Regensburg (BZR), Institut für Biochemie, Genetik und Mikrobiologie, Lehrstuhl Biochemie III, 93053 Regensburg, Germany.
authors.forename: Herbert
authors.initials: H
authors.lastname: Tschochner
authors.affiliation: Department of Integrated Structural Biology, IGBMC (Institut de Génétique et de Biologie Moléculaire et Cellulaire) INSERM, U964; CNRS/Strasbourg University, UMR7104 1, rue Laurent Fries, BP10142, 67404 Illkirch, France.
authors.forename: Patrick
authors.identifier: 0000-0002-7310-6186
authors.initials: P
authors.lastname: Schultz
mesh_terms: D020285:Cryoelectron Microscopy / Q000379:methods; D035463:Pol1 Transcription Initiation Complex Proteins / Q000235:genetics / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D000072417:Protein Domains; D055503:Protein Multimerization; D012318:RNA Polymerase I / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic
chemical_list: D035463:Pol1 Transcription Initiation Complex Proteins; C101161:RRN3 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D012318:RNA Polymerase I