title: The histone chaperones Nap1 and Vps75 bind histones H3 and H4 in a tetrameric conformation.
abstract: Histone chaperones physically interact with histones to direct proper assembly and disassembly of nucleosomes regulating diverse nuclear processes such as DNA replication, promoter remodeling, transcription elongation, DNA damage, and histone variant exchange. Currently, the best-characterized chaperone-histone interaction is that between the ubiquitous chaperone Asf1 and a dimer of H3 and H4. Nucleosome assembly proteins (Nap proteins) represent a distinct class of histone chaperone. Using pulsed electron double resonance (PELDOR) measurements and protein crosslinking, we show that two members of this class, Nap1 and Vps75, bind histones in the tetrameric conformation also observed when they are sequestered within the nucleosome. Furthermore, H3 and H4 trapped in their tetrameric state can be used as substrates in nucleosome assembly and chaperone-mediated lysine acetylation. This alternate mode of histone interaction provides a potential means of maintaining the integrity of the histone tetramer during cycles of nucleosome reassembly.
authors.affiliation: Wellcome Trust Centre for Gene Regulation and Expression, College of Life Sciences, University of Dundee, Dundee DD15EH, UK.
authors.forename: Andrew
authors.initials: A
authors.lastname: Bowman
authors.forename: Richard
authors.initials: R
authors.lastname: Ward
authors.forename: Nicola
authors.initials: N
authors.lastname: Wiechens
authors.forename: Vijender
authors.initials: V
authors.lastname: Singh
authors.forename: Hassane
authors.initials: H
authors.lastname: El-Mkami
authors.forename: David George
authors.initials: DG
authors.lastname: Norman
authors.forename: Tom
authors.initials: T
authors.lastname: Owen-Hughes
mesh_terms: D000107:Acetylation; D001665:Binding Sites; D004261:DNA Replication; D056488:Histone Chaperones / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D006657:Histones / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D008954:Models, Biological; D009707:Nucleosomes / Q000378:metabolism
chemical_list: D056488:Histone Chaperones; D006657:Histones; D009707:Nucleosomes