title: Local nucleosome dynamics facilitate chromatin accessibility in living mammalian cells.
abstract: Genome information, which is three-dimensionally organized within cells as chromatin, is searched and read by various proteins for diverse cell functions. Although how the protein factors find their targets remains unclear, the dynamic and flexible nature of chromatin is likely crucial. Using a combined approach of fluorescence correlation spectroscopy, single-nucleosome imaging, and Monte Carlo computer simulations, we demonstrate local chromatin dynamics in living mammalian cells. We show that similar to interphase chromatin, dense mitotic chromosomes also have considerable chromatin accessibility. For both interphase and mitotic chromatin, we observed local fluctuation of individual nucleosomes (~50 nm movement/30 ms), which is caused by confined Brownian motion. Inhibition of these local dynamics by crosslinking impaired accessibility in the dense chromatin regions. Our findings show that local nucleosome dynamics drive chromatin accessibility. We propose that this local nucleosome fluctuation is the basis for scanning genome information.
authors.affiliation: Biological Macromolecules Laboratory, Structural Biology Center, National Institute of Genetics, Mishima, Shizuoka 411-8540, Japan.
authors.forename: Saera
authors.initials: S
authors.lastname: Hihara
authors.forename: Chan-Gi
authors.initials: CG
authors.lastname: Pack
authors.forename: Kazunari
authors.initials: K
authors.lastname: Kaizu
authors.forename: Tomomi
authors.initials: T
authors.lastname: Tani
authors.forename: Tomo
authors.initials: T
authors.lastname: Hanafusa
authors.forename: Tadasu
authors.initials: T
authors.lastname: Nozaki
authors.forename: Satoko
authors.initials: S
authors.lastname: Takemoto
authors.forename: Tomohiko
authors.initials: T
authors.lastname: Yoshimi
authors.forename: Hideo
authors.initials: H
authors.lastname: Yokota
authors.forename: Naoko
authors.initials: N
authors.lastname: Imamoto
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Sako
authors.forename: Masataka
authors.initials: M
authors.lastname: Kinjo
authors.forename: Koichi
authors.initials: K
authors.lastname: Takahashi
authors.forename: Takeharu
authors.initials: T
authors.lastname: Nagai
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Maeshima
mesh_terms: D002460:Cell Line; D042002:Chromatin Assembly and Disassembly / Q000502:physiology*; D002877:Chromosomes, Human / Q000378:metabolism*; D003198:Computer Simulation; D006801:Humans; D007399:Interphase / Q000502:physiology*; D008856:Microscopy, Fluorescence; D008954:Models, Biological; D009707:Nucleosomes / Q000378:metabolism*
chemical_list: D009707:Nucleosomes