title: Stalled RNAP-II molecules bound to non-coding rDNA spacers are required for normal nucleolus architecture.
abstract: The correct distribution of nuclear domains is critical for the maintenance of normal cellular processes such as transcription and replication, which are regulated depending on their location and surroundings. The most well-characterized nuclear domain, the nucleolus, is essential for cell survival and metabolism. Alterations in nucleolar structure affect nuclear dynamics; however, how the nucleolus and the rest of the nuclear domains are interconnected is largely unknown. In this report, we demonstrate that RNAP-II is vital for the maintenance of the typical crescent-shaped structure of the nucleolar rDNA repeats and rRNA transcription. When stalled RNAP-II molecules are not bound to the chromatin, the nucleolus loses its typical crescent-shaped structure. However, the RNAP-II interaction with Seh1p, or cryptic transcription by RNAP-II, is not critical for morphological changes.
authors.affiliation: MRC Clinical Sciences Centre, Imperial College, London, W12 0NN, UK.
authors.forename: M A
authors.initials: MA
authors.lastname: Freire-Picos
authors.forename: V
authors.initials: V
authors.lastname: Landeira-Ameijeiras
authors.forename: María D
authors.initials: MD
authors.lastname: Mayán
mesh_terms: D002466:Cell Nucleolus / Q000378:metabolism / Q000648:ultrastructure*; D002843:Chromatin / Q000378:metabolism; D004261:DNA Replication; D021903:DNA, Ribosomal Spacer / Q000378:metabolism*; D015966:Gene Expression Regulation, Fungal; D009154:Mutation; D009697:Nucleolus Organizer Region / Q000378:metabolism / Q000648:ultrastructure; D025941:Protein Interaction Mapping; D012318:RNA Polymerase I / Q000235:genetics / Q000378:metabolism; D012319:RNA Polymerase II / Q000235:genetics / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D013696:Temperature; D014158:Transcription, Genetic
chemical_list: D002843:Chromatin; D021903:DNA, Ribosomal Spacer; D012319:RNA Polymerase II; D012318:RNA Polymerase I
keywords: Nup84; RNAP-II; Seh1p; non-coding regions; nucleolus; rDNA; α-amanitin