Saera Hihara, Chan-Gi Pack, Kazunari Kaizu, Tomomi Tani, Tomo Hanafusa, Tadasu Nozaki, Satoko Takemoto, Tomohiko Yoshimi, Hideo Yokota, Naoko Imamoto, Yasushi Sako, Masataka Kinjo, Koichi Takahashi, Takeharu Nagai, Kazuhiro Maeshima (2012) Local nucleosome dynamics facilitate chromatin accessibility in living mammalian cells., Cell reports, Volume 2, Number 6, pp. 1645-56
Published in 2012 Dec 27 (Electronic publication in Dec. 13, 2012, midnight )
(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.(MeSH Terms)