title: Subnuclear partitioning of rRNA genes between the nucleolus and nucleoplasm reflects alternative epiallelic states.
abstract: Eukaryotes can have thousands of 45S ribosomal RNA (rRNA) genes, many of which are silenced during development. Using fluorescence-activated sorting techniques, we show that active rRNA genes in Arabidopsis thaliana are present within sorted nucleoli, whereas silenced rRNA genes are excluded. DNA methyltransferase (met1), histone deacetylase (hda6), or chromatin assembly (caf1) mutants that disrupt silencing abrogate this nucleoplasmic-nucleolar partitioning. Bisulfite sequencing data indicate that active nucleolar rRNA genes are nearly completely demethylated at promoter CGs, whereas silenced genes are nearly fully methylated. Collectively, the data reveal that rRNA genes occupy distinct but changeable nuclear territories according to their epigenetic state.
authors.affiliation: Department of Biology, Indiana University, Bloomington, Indiana 47405,USA. frederic.pontvianne@univ-perp.fr
authors.forename: Frederic
authors.initials: F
authors.lastname: Pontvianne
authors.forename: Todd
authors.initials: T
authors.lastname: Blevins
authors.forename: Chinmayi
authors.initials: C
authors.lastname: Chandrasekhara
authors.forename: Iva
authors.initials: I
authors.lastname: Mozgová
authors.forename: Christiane
authors.initials: C
authors.lastname: Hassel
authors.forename: Olga M F
authors.initials: OM
authors.lastname: Pontes
authors.forename: Sarah
authors.initials: S
authors.lastname: Tucker
authors.forename: Petr
authors.initials: P
authors.lastname: Mokros
authors.forename: Veronika
authors.initials: V
authors.lastname: Muchová
authors.forename: Jirí
authors.initials: J
authors.lastname: Fajkus
authors.forename: Craig S
authors.initials: CS
authors.lastname: Pikaard
mesh_terms: D017360:Arabidopsis / Q000235:genetics*; D029681:Arabidopsis Proteins / Q000235:genetics*; D002466:Cell Nucleolus / Q000378:metabolism*; D002467:Cell Nucleus / Q000378:metabolism*; D019175:DNA Methylation; D044127:Epigenesis, Genetic; D018506:Gene Expression Regulation, Plant; D020868:Gene Silencing; D008957:Models, Genetic; D009154:Mutation; D012335:RNA, Ribosomal / Q000235:genetics*
chemical_list: D029681:Arabidopsis Proteins; D012335:RNA, Ribosomal; C088179:RNA, ribosomal, 45S
keywords: DNA methylation; RNA polymerase I; chromatin assembly; gene silencing; histone deacetylation; ribosomal RNA gene; transcription