title: Sharing of mitotic pre-ribosomal particles between daughter cells.
abstract: Ribosome biogenesis is a fundamental multistep process initiated by the synthesis of 90S pre-ribosomal particles in the nucleoli of higher eukaryotes. Even though synthesis of ribosomes stops during mitosis while nucleoli disappear, mitotic pre-ribosomal particles persist as observed in pre-nucleolar bodies (PNBs) during telophase. To further understand the relationship between the nucleolus and the PNBs, the presence and the fate of the mitotic pre-ribosomal particles during cell division were investigated. We demonstrate that the recently synthesized 45S precursor ribosomal RNAs (pre-rRNAs) as well as the 32S and 30S pre-rRNAs are maintained during mitosis and associated with the chromosome periphery together with pre-rRNA processing factors. Maturation of the mitotic pre-ribosomal particles, as assessed by the stability of the mitotic pre-rRNAs, is transiently arrested during mitosis by a cyclin-dependent kinase (CDK)1-cyclin-B-dependent mechanism and can be restored by CDK inhibitor treatments. At the M-G1 transition, the resumption of mitotic pre-rRNA processing in PNBs does not induce the disappearance of PNBs; this only occurs when functional nucleoli reform. Strikingly, during their maturation process, mitotic pre-rRNAs localize in reforming nucleoli.
authors.affiliation: Université Paris Diderot, Unit of Functional and Adaptive Biology, UMR 8251 CNRS, 4 rue Marie-Andrée Lagroua Weill-Hallé, Paris F-75205, France.
authors.forename: Valentina
authors.initials: V
authors.lastname: Sirri
authors.affiliation: UPMC Université Paris 06, Institut de Biologie Paris Seine, UMR 8256 CNRS, 9 quai St Bernard, Paris F-75252, France.
authors.forename: Nathalie
authors.initials: N
authors.lastname: Jourdan
authors.affiliation: Université Paris Diderot, Institut Jacques Monod, UMR 7592 CNRS, 15 rue Hélène Brion, Paris F-75205, France.
authors.forename: Danièle
authors.initials: D
authors.lastname: Hernandez-Verdun
authors.affiliation: Université Paris Diderot, Unit of Functional and Adaptive Biology, UMR 8251 CNRS, 4 rue Marie-Andrée Lagroua Weill-Hallé, Paris F-75205, France p.roussel@univ-paris-diderot.fr.
authors.forename: Pascal
authors.initials: P
authors.lastname: Roussel
mesh_terms: D016203:CDC2 Protein Kinase / Q000378:metabolism*; D002466:Cell Nucleolus / Q000378:metabolism*; D059585:G1 Phase Cell Cycle Checkpoints; D006367:HeLa Cells; D006801:Humans; D008938:Mitosis; D012322:RNA Precursors / Q000378:metabolism*; D012323:RNA Processing, Post-Transcriptional; D012335:RNA, Ribosomal / Q000378:metabolism*; D012270:Ribosomes / Q000378:metabolism*
chemical_list: D012322:RNA Precursors; D012335:RNA, Ribosomal; C088179:RNA, ribosomal, 45S; D016203:CDC2 Protein Kinase
keywords: Mitosis; Nucleolus; PNB; Ribosomal RNA