title: H2A.Z.2.2 is an alternatively spliced histone H2A.Z variant that causes severe nucleosome destabilization.
abstract: The histone variant H2A.Z has been implicated in many biological processes, such as gene regulation and genome stability. Here, we present the identification of H2A.Z.2.2 (Z.2.2), a novel alternatively spliced variant of histone H2A.Z and provide a comprehensive characterization of its expression and chromatin incorporation properties. Z.2.2 mRNA is found in all human cell lines and tissues with highest levels in brain. We show the proper splicing and in vivo existence of this variant protein in humans. Furthermore, we demonstrate the binding of Z.2.2 to H2A.Z-specific TIP60 and SRCAP chaperone complexes and its active replication-independent deposition into chromatin. Strikingly, various independent in vivo and in vitro analyses, such as biochemical fractionation, comparative FRAP studies of GFP-tagged H2A variants, size exclusion chromatography and single molecule FRET, in combination with in silico molecular dynamics simulations, consistently demonstrate that Z.2.2 causes major structural changes and significantly destabilizes nucleosomes. Analyses of deletion mutants and chimeric proteins pinpoint this property to its unique C-terminus. Our findings enrich the list of known human variants by an unusual protein belonging to the H2A.Z family that leads to the least stable nucleosome known to date.
authors.affiliation: Department of Molecular Biology, Adolf-Butenandt-Institute, Ludwig-Maximilians-University Munich, 80336 Munich, Germany.
authors.forename: Clemens
authors.initials: C
authors.lastname: Bönisch
authors.forename: Katrin
authors.initials: K
authors.lastname: Schneider
authors.forename: Sebastian
authors.initials: S
authors.lastname: Pünzeler
authors.forename: Sonja M
authors.initials: SM
authors.lastname: Wiedemann
authors.forename: Christina
authors.initials: C
authors.lastname: Bielmeier
authors.forename: Marco
authors.initials: M
authors.lastname: Bocola
authors.forename: H Christian
authors.initials: HC
authors.lastname: Eberl
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Kuegel
authors.forename: Jürgen
authors.initials: J
authors.lastname: Neumann
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Kremmer
authors.forename: Heinrich
authors.initials: H
authors.lastname: Leonhardt
authors.forename: Matthias
authors.initials: M
authors.lastname: Mann
authors.forename: Jens
authors.initials: J
authors.lastname: Michaelis
authors.forename: Lothar
authors.initials: L
authors.lastname: Schermelleh
authors.forename: Sandra B
authors.initials: SB
authors.lastname: Hake
mesh_terms: D000251:Adenosine Triphosphatases / Q000378:metabolism; D017398:Alternative Splicing; D002460:Cell Line; D002843:Chromatin / Q000378:metabolism; D004247:DNA / Q000378:metabolism; D051548:Histone Acetyltransferases / Q000378:metabolism; D006657:Histones / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism / Q000502:physiology*; D006801:Humans; D000074443:Lysine Acetyltransferase 5; D009707:Nucleosomes / Q000378:metabolism*; D020033:Protein Isoforms / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D017434:Protein Structure, Tertiary
chemical_list: D002843:Chromatin; D006657:Histones; D009707:Nucleosomes; D020033:Protein Isoforms; C077020:histone H2A.F-Z; D004247:DNA; D051548:Histone Acetyltransferases; C098489:KAT5 protein, human; D000074443:Lysine Acetyltransferase 5; D000251:Adenosine Triphosphatases; C119652:SRCAP protein, human