title: Opposing roles of H3- and H4-acetylation in the  regulation of nucleosome structure––a FRET study.
abstract: Using FRET in bulk and on single molecules, we assessed the structural role of histone acetylation in nucleosomes reconstituted on the 170 bp long Widom 601 sequence. We followed salt-induced nucleosome disassembly, using donor–acceptor pairs on the ends or in the internal part of the nucleosomal DNA, and on H2B histone for measuring H2A/H2B dimer exchange. This allowed us to distinguish the influence of acetylation on salt-induced DNA unwrapping at the entry–exit site from its effect on nucleosome core dissociation. The effect of lysine acetylation is not simply cumulative, but showed distinct histone-specificity. Both H3- and H4-acetylation enhance DNA unwrapping above physiological ionic strength; however, while H3-acetylation renders the nucleosome core more sensitive to salt-induced dissociation and to dimer exchange, H4-acetylation counteracts these effects. Thus, our data suggest, that H3- and H4-acetylation have partially opposing roles in regulating nucleosome architecture and that distinct aspects of nucleosome dynamics might be independently controlled by individual histones.
authors.forename: Alexander
authors.initials: A
authors.lastname: Gansen
authors.forename: Katalin
authors.initials: K
authors.lastname: Tóth
authors.forename: Nathalie
authors.initials: N
authors.lastname: Schwarz
authors.forename: Jörg
authors.initials: J
authors.lastname: Langowski
mesh_terms: D000107:Acetylation; D019281:Dimerization; D024202:Electrophoretic Mobility Shift Assay; D031541:Fluorescence Resonance Energy Transfer; D006657:Histones / Q000378:metabolism*; D009707:Nucleosomes / Q000378:metabolism*
chemical_list: D006657:Histones; D009707:Nucleosomes