title: Ribosomal chromatin organization.
abstract: Mammalian cells contain approximately 400 copies of the ribosomal RNA genes organized as tandem, head-to-tail repeats spread among 6-8 chromosomes. Only a subset of the genes is transcribed at any given time. Experimental evidence suggests that, in a specific cell type, only a fraction of the genes exists in a conformation that can be transcribed. An increasing body of study indicates that eukaryotic ribosomal RNA genes exist in either a heterochromatic nucleosomal state or in open euchromatic states in which they can be, or are, transcribed. This review will attempt to summarize our current understanding of the structure and organization of ribosomal chromatin.
authors.affiliation: Department of Cell and Molecular Biology, The Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA. s-huang2@northwestern.edu
authors.forename: Sui
authors.initials: S
authors.lastname: Huang
authors.forename: Lawrence I
authors.initials: LI
authors.lastname: Rothblum
authors.forename: Danyang
authors.initials: D
authors.lastname: Chen
mesh_terms: D000818:Animals; D002843:Chromatin / Q000235:genetics / Q000378:metabolism*; D004271:DNA, Fungal / Q000378:metabolism*; D004275:DNA, Ribosomal / Q000378:metabolism*; D006570:Heterochromatin / Q000235:genetics / Q000378:metabolism; D008957:Models, Genetic; D012270:Ribosomes / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic
chemical_list: D002843:Chromatin; D004271:DNA, Fungal; D004275:DNA, Ribosomal; D006570:Heterochromatin