The dynamic assembly of distinct RNA polymerase I complexes modulates rDNA transcription
- Centro de Investigaciones Biológicas, Spain
- The Barcelona Institute of Science and Technology, Spain
- Instituto de Biología Funcional y Genómica, Spain
- Cooperative Center for Research in Biosciences CIC bioGUNE, Spain
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.
Article and author information
Author details
Jaime Alegrio Louro
Funding
Ministerio de Economía y Competitividad (BFU2013-48374-P)
- Carlos Fernández-Tornero
Fundación Ramón Areces (-)
- Carlos Fernández-Tornero
Ministerio de Economía y Competitividad (RYC-2011-07967)
- Oriol Gallego
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Copyright
© 2017, Torreira et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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The dynamic assembly of distinct RNA polymerase I complexes modulates rDNA transcription
eLife 6:e20832.
https://doi.org/10.7554/eLife.20832
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