2026-04-10 京都大学
クライオ電子顕微鏡（Cryo-EM）法、粗視化分子動力学計算（CGMD）、核磁気共鳴（NMR）法を用いて核内で遺伝子の発現が活性なユークロマチン形成と不活性なヘテロクロマチン形成に関与するクロマチンの構成単位であるヌクレオソーム中のヒストンの化学修飾（アセチル化）とヒストンH1の役割の分子機構を解明した。
＜関連情報＞
- https://www.kyoto-u.ac.jp/ja/research-news/2026-04-10-3
- https://www.kyoto-u.ac.jp/sites/default/files/2026-04/web_2604_Furukawa-1bfb485be35d7b55947f60e1a1b824a1.pdf
- https://www.nature.com/articles/s42003-026-09926-y
リンカーヒストンH1は、H4テールアセチル化によって誘導されるH3テールアセチル化を抑制し、その動態を変化させる Linker histone H1 represses H3 tail acetylation induced by H4 tail acetylation and alters its dynamics
Ayako Furukawa,Kenta Echigoya,Samuel Blazquez,Masatoshi Wakamori,Hideaki Ohtomo,Yasuo Tsunaka,Takashi Umehara,Tsuyoshi Terakawa,Yoshimasa Takizawa,Hitoshi Kurumizaka & Yoshifumi Nishimura
Communications Biology Published:09 April 2026
DOI:https://doi.org/10.1038/s42003-026-09926-y
Abstract
The nucleosome is the fundamental chromatin unit, containing two copies of histones H2A, H2B, H3, and H4 wrapped by ~ 146 bp of core DNA plus linker DNA; addition of linker histone H1 forms a chromatosome. Tetra-acetylation of the H4 N-terminal tail (H4-4Kac) enhances H3 N-tail acetylation by altering their mutual dynamics, but how H1 influences these dynamics remains unclear. Using cryo-electron microscopy and coarse-grained molecular dynamics simulations, we show that H4-4Kac and unmodified chromatosomes share essentially identical core histone–DNA structures and similar H3 N-tail dynamics. However, nuclear magnetic resonance spectroscopy reveals that in the H4-4Kac chromatosome, the H3 N-tail adopts a dynamically robust DNA-contact state distinct from that in the unmodified chromatosome, resulting in markedly reduced H3 N-tail acetylation. These findings suggest that linker histone H1 suppresses the progression of euchromatin formation.
