title: Linker histone H1 and H3K56 acetylation are antagonistic regulators of nucleosome dynamics.
abstract: H1 linker histones are highly abundant proteins that compact nucleosomes and chromatin to regulate DNA accessibility and transcription. However, the mechanisms that target H1 regulation to specific regions of eukaryotic genomes are unknown. Here we report fluorescence measurements of human H1 regulation of nucleosome dynamics and transcription factor (TF) binding within nucleosomes. H1 does not block TF binding, instead it suppresses nucleosome unwrapping to reduce DNA accessibility within H1-bound nucleosomes. We then investigated H1 regulation by H3K56 and H3K122 acetylation, two transcriptional activating histone post translational modifications (PTMs). Only H3K56 acetylation, which increases nucleosome unwrapping, abolishes H1.0 reduction of TF binding. These findings show that nucleosomes remain dynamic, while H1 is bound and H1 dissociation is not required for TF binding within the nucleosome. Furthermore, our H3K56 acetylation measurements suggest that a single-histone PTM can define regions of the genome that are not regulated by H1.
authors.affiliation: Department of Physics, The Ohio State University, Columbus, Ohio 43210, USA.
authors.forename: Morgan
authors.initials: M
authors.lastname: Bernier
authors.affiliation: Biophysics Graduate Program, The Ohio State University, Columbus, Ohio 43210, USA.
authors.forename: Yi
authors.initials: Y
authors.lastname: Luo
authors.affiliation: Department of Physics, The Ohio State University, Columbus, Ohio 43210, USA.
authors.forename: Kingsley C
authors.initials: KC
authors.lastname: Nwokelo
authors.affiliation: Department of Physics, The Ohio State University, Columbus, Ohio 43210, USA.
authors.forename: Michelle
authors.initials: M
authors.lastname: Goodwin
authors.affiliation: The Ohio State Biochemistry Program, The Ohio State University, Columbus, Ohio 43210, USA.
authors.forename: Sarah J
authors.initials: SJ
authors.lastname: Dreher
authors.affiliation: Department of Biological Chemistry and Pharmacology, The Ohio State University, Columbus, Ohio 43210, USA.
authors.forename: Pei
authors.initials: P
authors.lastname: Zhang
authors.affiliation: Department of Biological Chemistry and Pharmacology, The Ohio State University, Columbus, Ohio 43210, USA.
authors.forename: Mark R
authors.initials: MR
authors.lastname: Parthun
authors.affiliation: Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, Kentucky 40536, USA.
authors.forename: Yvonne
authors.initials: Y
authors.lastname: Fondufe-Mittendorf
authors.affiliation: Biophysics Graduate Program, The Ohio State University, Columbus, Ohio 43210, USA.|The Ohio State Biochemistry Program, The Ohio State University, Columbus, Ohio 43210, USA.|Department of Chemistry &Biochemistry, The Ohio State University, Columbus, Ohio 43210, USA.
authors.forename: Jennifer J
authors.initials: JJ
authors.lastname: Ottesen
authors.affiliation: Department of Physics, The Ohio State University, Columbus, Ohio 43210, USA.|Biophysics Graduate Program, The Ohio State University, Columbus, Ohio 43210, USA.|The Ohio State Biochemistry Program, The Ohio State University, Columbus, Ohio 43210, USA.|Department of Chemistry &Biochemistry, The Ohio State University, Columbus, Ohio 43210, USA.
authors.forename: Michael G
authors.initials: MG
authors.lastname: Poirier
mesh_terms: D000107:Acetylation; D020816:Amino Acid Motifs; D002843:Chromatin; D006657:Histones / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D009707:Nucleosomes / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D002843:Chromatin; D006657:Histones; D009707:Nucleosomes; D014157:Transcription Factors