title: Is ribosome synthesis controlled by pol I transcription?
abstract: Regulation of growth ultimately depends on the control of synthesis of new ribosomes. Ribosome biogenesis is thus a key element of cell biology, which is tightly regulated in response to environmental conditions. In eukaryotic cells, the supply of ribosomal components involves the activities of the three forms of nuclear RNA polymerase (Pol I, Pol II and Pol III). Recently, we demonstrated that upon rapamycin treatment, a partial derepression of Pol I transcription led to a concomitant derepression of Pol II transcription restricted to a small subset of class II genes encompassing the genes encoding all ribosomal proteins, and 19 additional genes. The products of 14 of these 19 genes are principally involved in rDNA structure, ribosome biogenesis or translation, whereas the five remaining genes code for hypothetical proteins. We demonstrate that the proteins encoded by these five genes are required for optimal pre-rRNA processing. In addition, we show that cells in which regulation of Pol I transcription was specifically impaired are either resistant or hypersensitive to different stresses compared to wild-type cells. These results highlight the critical role of the regulation of Pol I activity for the physiology of the cells.
authors.affiliation: CEA, Laboratoire Régulation de l'Expression des Gènes et Epigénétique, Service de Biologie Integrative et Génétique Moléculaire, Gif sur Yvette, France.
authors.forename: Stéphane
authors.initials: S
authors.lastname: Chédin
authors.forename: Arnaud
authors.initials: A
authors.lastname: Laferté
authors.forename: Tran
authors.initials: T
authors.lastname: Hoang
authors.forename: Denis L J
authors.initials: DL
authors.lastname: Lafontaine
authors.forename: Michel
authors.initials: M
authors.lastname: Riva
authors.forename: Christophe
authors.initials: C
authors.lastname: Carles
mesh_terms: D000818:Animals; D006801:Humans; D012318:RNA Polymerase I / Q000096:biosynthesis* / Q000235:genetics* / Q000502:physiology; D012270:Ribosomes / Q000201:enzymology* / Q000235:genetics; D014158:Transcription, Genetic / Q000502:physiology*
chemical_list: D012318:RNA Polymerase I