著者

前島 一博 城地 保昌 西野 吉則 高田 英昭 鎌田 福美 日原 さえら

出版者

一般社団法人 日本生物物理学会

雑誌

生物物理 (ISSN:05824052)

巻号頁・発行日

vol.53, no.1, pp.004-010, 2013 (Released:2013-01-29)

参考文献数

29

---

How is 2-m-long genomic DNA organized into a mitotic chromosome or nucleus? The nucleosome fiber has long been assumed to be folded into a 30-nm chromatin fiber, and further helically folded larger fiber. However, when we observed frozen hydrated human mitotic cells using cryoelectron microscopy (cryo-EM), no higher-order structures including 30-nm chromatin fibers were found. To further investigate the bulk structure of mitotic chromosomes, we performed small-angle X-ray scattering (SAXS) at SPring-8. No structural feature larger than 11 nm was detected, even on a chromosome-diameter scale (~1 μm). We also found a similar scattering pattern in interphase nuclei of HeLa cells in the range up to ~275 nm. Our findings suggest a common structural feature in interphase and mitotic chromatins: compact and irregular folding of nucleosome fibers occurs without a 30-nm chromatin structure.