title: Nucleosome assembly protein 1 exchanges histone H2A-H2B dimers and assists nucleosome sliding.
abstract: Eukaryotic chromatin is highly dynamic and turns over rapidly even in the absence of DNA replication. Here we show that the acidic histone chaperone nucleosome assembly protein 1 (NAP-1) from yeast reversibly removes and replaces histone protein dimer H2A-H2B or histone variant dimers from assembled nucleosomes, resulting in active histone exchange. Transient removal of H2A-H2B dimers facilitates nucleosome sliding along the DNA to a thermodynamically favorable position. Histone exchange as well as nucleosome sliding is independent of ATP and relies on the presence of the C-terminal acidic domain of yeast NAP-1, even though this region is not required for histone binding and chromatin assembly. Our results suggest a novel role for NAP-1 (and perhaps other acidic histone chaperones) in mediating chromatin fluidity by incorporating histone variants and assisting nucleosome sliding. NAP-1 may function either untargeted (if acting alone) or may be targeted to specific regions within the genome through interactions with additional factors.
authors.affiliation: Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado 80523-1870, USA.
authors.forename: Young-Jun
authors.initials: YJ
authors.lastname: Park
authors.forename: Jayanth V
authors.initials: JV
authors.lastname: Chodaparambil
authors.forename: Yunhe
authors.initials: Y
authors.lastname: Bao
authors.forename: Steven J
authors.initials: SJ
authors.lastname: McBryant
authors.forename: Karolin
authors.initials: K
authors.lastname: Luger
mesh_terms: D018797:Cell Cycle Proteins; D019281:Dimerization; D006657:Histones / Q000737:chemistry / Q000378:metabolism*; D009687:Nuclear Proteins; D056490:Nucleosome Assembly Protein 1; D011506:Proteins / Q000378:metabolism*; D013816:Thermodynamics
chemical_list: D018797:Cell Cycle Proteins; D006657:Histones; D009687:Nuclear Proteins; D056490:Nucleosome Assembly Protein 1; D011506:Proteins