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[Report] Crystal structure of the overlapping dinucleosome composed of hexasome and octasome

ScienceNOW - Fetched: April 13th, 2017, 3:00pm UTC

Nucleosomes are dynamic entities that are repositioned along DNA by chromatin remodeling processes. A nucleosome repositioned by the switch-sucrose nonfermentable (SWI/SNF) remodeler collides with a neighbor and forms the intermediate “overlapping dinucleosome.” Here, we report the crystal structure of the overlapping dinucleosome, in which two nucleosomes are associated, at 3.14-angstrom resolution. In the overlapping dinucleosome structure, the unusual “hexasome” nucleosome, composed of the histone hexamer lacking one H2A-H2B dimer from the conventional histone octamer, contacts the canonical “octasome” nucleosome, and they intimately associate. Consequently, about 250 base pairs of DNA are left-handedly wrapped in three turns, without a linker DNA segment between the hexasome and octasome moieties. The overlapping dinucleosome structure may provide important information to understand how nucleosome repositioning occurs during the chromatin remodeling process. Authors: Daiki Kato, Akihisa Osakabe, Yasuhiro Arimura, Yuka Mizukami, Naoki Horikoshi, Kazumi Saikusa, Satoko Akashi, Yoshifumi Nishimura, Sam-Yong Park, Jumpei Nogami, Kazumitsu Maehara, Yasuyuki Ohkawa, Atsushi Matsumoto, Hidetoshi Kono, Rintaro Inoue, Masaaki Sugiyama, Hitoshi Kurumizaka

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