title: The dynamic assembly of distinct RNA polymerase I complexes modulates rDNA transcription.
abstract: Cell growth requires synthesis of ribosomal RNA by RNA polymerase I (Pol I). Binding of initiation factor Rrn3 activates Pol I, fostering recruitment to ribosomal DNA promoters. This fundamental process must be precisely regulated to satisfy cell needs at any time. We present in vivo evidence that, when growth is arrested by nutrient deprivation, cells induce rapid clearance of Pol I-Rrn3 complexes, followed by the assembly of inactive Pol I homodimers. This dual repressive mechanism reverts upon nutrient addition, thus restoring cell growth. Moreover, Pol I dimers also form after inhibition of either ribosome biogenesis or protein synthesis. Our mutational analysis, based on the electron cryomicroscopy structures of monomeric Pol I alone and in complex with Rrn3, underscores the central role of subunits A43 and A14 in the regulation of differential Pol I complexes assembly and subsequent promoter association.
authors.affiliation: IPSBB Unit, Centro de Investigaciones Biológicas, Madrid, Spain.
authors.forename: Eva
authors.initials: E
authors.lastname: Torreira
authors.affiliation: IPSBB Unit, Centro de Investigaciones Biológicas, Madrid, Spain.
authors.forename: Jaime Alegrio
authors.identifier: 0000-0002-2800-923X
authors.initials: JA
authors.lastname: Louro
authors.affiliation: Institute for Research in Biomedicine, Barcelona, Spain.|The Barcelona Institute of Science and Technology, Barcelona, Spain.
authors.forename: Irene
authors.initials: I
authors.lastname: Pazos
authors.affiliation: Instituto de Biología Funcional y Genómica, CSIC-Universidad de Salamanca, Salamanca, Spain.
authors.forename: Noelia
authors.initials: N
authors.lastname: González-Polo
authors.affiliation: Structural Biology Unit, Cooperative Center for Research in Biosciences CIC bioGUNE, Derio, Spain.
authors.forename: David
authors.initials: D
authors.lastname: Gil-Carton
authors.affiliation: Institute for Research in Biomedicine, Barcelona, Spain.|The Barcelona Institute of Science and Technology, Barcelona, Spain.
authors.forename: Ana Garcia
authors.initials: AG
authors.lastname: Duran
authors.affiliation: Institute for Research in Biomedicine, Barcelona, Spain.|The Barcelona Institute of Science and Technology, Barcelona, Spain.
authors.forename: Sébastien
authors.initials: S
authors.lastname: Tosi
authors.affiliation: Institute for Research in Biomedicine, Barcelona, Spain.|The Barcelona Institute of Science and Technology, Barcelona, Spain.
authors.forename: Oriol
authors.initials: O
authors.lastname: Gallego
authors.affiliation: Instituto de Biología Funcional y Genómica, CSIC-Universidad de Salamanca, Salamanca, Spain.
authors.forename: Olga
authors.initials: O
authors.lastname: Calvo
authors.affiliation: IPSBB Unit, Centro de Investigaciones Biológicas, Madrid, Spain.
authors.forename: Carlos
authors.identifier: 0000-0001-5097-731X
authors.initials: C
authors.lastname: Fernández-Tornero
mesh_terms: D020285:Cryoelectron Microscopy; D004252:DNA Mutational Analysis; D004275:DNA, Ribosomal / Q000235:genetics*; D035463:Pol1 Transcription Initiation Complex Proteins / Q000378:metabolism*; D011485:Protein Binding; D055503:Protein Multimerization; D012318:RNA Polymerase I / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism*; D014158:Transcription, Genetic
chemical_list: D004275:DNA, Ribosomal; D035463:Pol1 Transcription Initiation Complex Proteins; C101161:RRN3 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D012318:RNA Polymerase I
keywords: RNA polymerase I; Rrn3; S. cerevisiae; chromosomes; genes; growth control; ribosomal RNA synthesis; transcriptional activation