Summary information and primary citation

PDB-id
7dbh; SNAP-derived features in text and JSON formats; DNAproDB
Class
DNA binding protein
Method
cryo-EM (3.6 Å)
Summary
The mouse nucleosome structure containing h3mm18
Reference
Hirai S, Tomimatsu K, Miyawaki-Kuwakado A, Takizawa Y, Komatsu T, Tachibana T, Fukushima Y, Takeda Y, Negishi L, Kujirai T, Koyama M, Ohkawa Y, Kurumizaka H (2022): "Unusual nucleosome formation and transcriptome influence by the histone H3mm18 variant." Nucleic Acids Res., 50, 72-91. doi: 10.1093/nar/gkab1137.
Abstract
Histone H3mm18 is a non-allelic H3 variant expressed in skeletal muscle and brain in mice. However, its function has remained enigmatic. We found that H3mm18 is incorporated into chromatin in cells with low efficiency, as compared to H3.3. We determined the structures of the nucleosome core particle (NCP) containing H3mm18 by cryo-electron microscopy, which revealed that the entry/exit DNA regions are drastically disordered in the H3mm18 NCP. Consistently, the H3mm18 NCP is substantially unstable in vitro. The forced expression of H3mm18 in mouse myoblast C2C12 cells markedly suppressed muscle differentiation. A transcriptome analysis revealed that the forced expression of H3mm18 affected the expression of multiple genes, and suppressed a group of genes involved in muscle development. These results suggest a novel gene expression regulation system in which the chromatin landscape is altered by the formation of unusual nucleosomes with a histone variant, H3mm18, and provide important insight into understanding transcription regulation by chromatin.

Cartoon-block schematics in six views (download the tarball)

PyMOL session file Download PDB file View in 3Dmol.js