title: The prenucleosome, a stable conformational isomer of the nucleosome.
abstract: Chromatin comprises nucleosomes as well as nonnucleosomal histone-DNA particles. Prenucleosomes are rapidly formed histone-DNA particles that can be converted into canonical nucleosomes by a motor protein such as ACF. Here we show that the prenucleosome is a stable conformational isomer of the nucleosome. It consists of a histone octamer associated with ∼ 80 base pair (bp) of DNA, which is located at a position that corresponds to the central 80 bp of a nucleosome core particle. Monomeric prenucleosomes with free flanking DNA do not spontaneously fold into nucleosomes but can be converted into canonical nucleosomes by an ATP-driven motor protein such as ACF or Chd1. In addition, histone H3K56, which is located at the DNA entry and exit points of a canonical nucleosome, is specifically acetylated by p300 in prenucleosomes relative to nucleosomes. Prenucleosomes assembled in vitro exhibit properties that are strikingly similar to those of nonnucleosomal histone-DNA particles in the upstream region of active promoters in vivo. These findings suggest that the prenucleosome, the only known stable conformational isomer of the nucleosome, is related to nonnucleosomal histone-DNA species in the cell.
authors.affiliation: Section of Molecular Biology, University of California at San Diego, La Jolla, California 92093, USA;
authors.forename: Jia
authors.initials: J
authors.lastname: Fei
authors.affiliation: Section of Molecular Biology, University of California at San Diego, La Jolla, California 92093, USA;
authors.forename: Sharon E
authors.initials: SE
authors.lastname: Torigoe
authors.affiliation: Department of Molecular, Cell, and Developmental Biology, University of California at Santa Cruz, Santa Cruz, California 95064, USA.
authors.forename: Christopher R
authors.initials: CR
authors.lastname: Brown
authors.affiliation: Section of Molecular Biology, University of California at San Diego, La Jolla, California 92093, USA;
authors.forename: Mai T
authors.initials: MT
authors.lastname: Khuong
authors.affiliation: Section of Molecular Biology, University of California at San Diego, La Jolla, California 92093, USA;
authors.forename: George A
authors.initials: GA
authors.lastname: Kassavetis
authors.affiliation: Department of Molecular, Cell, and Developmental Biology, University of California at Santa Cruz, Santa Cruz, California 95064, USA.
authors.forename: Hinrich
authors.initials: H
authors.lastname: Boeger
authors.affiliation: Section of Molecular Biology, University of California at San Diego, La Jolla, California 92093, USA;
authors.forename: James T
authors.initials: JT
authors.lastname: Kadonaga
mesh_terms: D000818:Animals; D002843:Chromatin / Q000378:metabolism*; D004247:DNA / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D006657:Histones / Q000378:metabolism; D006801:Humans; D008854:Microscopy, Electron; D009707:Nucleosomes / Q000737:chemistry / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D011401:Promoter Regions, Genetic; D011487:Protein Conformation; D055550:Protein Stability; D061987:Sf9 Cells
chemical_list: D002843:Chromatin; D006657:Histones; D009707:Nucleosomes; D004247:DNA
keywords: active chromatin; gene expression; histones; nucleosome; prenucleosome