title: An intranucleolar body associated with rDNA.
abstract: The nucleolus is the subnuclear organelle responsible for ribosome subunit biogenesis and can also act as a stress sensor. It forms around clusters of ribosomal DNA (rDNA) and is mainly organised in three subcompartments, i.e. fibrillar centre, dense fibrillar component and granular component. Here, we describe the localisation of 21 protein factors to an intranucleolar region different to these main subcompartments, called the intranucleolar body (INB). These factors include proteins involved in DNA maintenance, protein turnover, RNA metabolism, chromatin organisation and the post-translational modifiers SUMO1 and SUMO2/3. Increase in the size and number of INBs is promoted by specific types of DNA damage and depends on the functional integrity of the nucleolus. INBs are abundant in nucleoli of unstressed cells during S phase and localise in close proximity to rDNA with heterochromatic features. The data suggest the INB is linked with regulation of rDNA transcription and/or maintenance of rDNA.
authors.affiliation: Wellcome Trust Centre for Gene Regulation and Expression, College of Life Sciences, University of Dundee, UK.
authors.forename: Saskia
authors.initials: S
authors.lastname: Hutten
authors.forename: Alan
authors.initials: A
authors.lastname: Prescott
authors.forename: John
authors.initials: J
authors.lastname: James
authors.forename: Stefanie
authors.initials: S
authors.lastname: Riesenberg
authors.forename: Séverine
authors.initials: S
authors.lastname: Boulon
authors.forename: Yun Wah
authors.initials: YW
authors.lastname: Lam
authors.forename: Angus I
authors.initials: AI
authors.lastname: Lamond
mesh_terms: D000818:Animals; D002417:Cattle; D002460:Cell Line; D002466:Cell Nucleolus / Q000235:genetics* / Q000378:metabolism; D004275:DNA, Ribosomal / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D021381:Protein Transport; D011506:Proteins / Q000235:genetics / Q000378:metabolism; D012335:RNA, Ribosomal / Q000235:genetics / Q000378:metabolism; D012867:Skin / Q000166:cytology / Q000378:metabolism
chemical_list: D004275:DNA, Ribosomal; D011506:Proteins; D012335:RNA, Ribosomal