| Novel model for the chromatin structure | ||
| Current Opinion in Cell Biology 22 291-297, 2010. | ||
| Maeshima Laboratory, Biological Macromolecules Laboratory | ||
| Chromatin structure: does the 30-nm fibre exist in vivo? Kazuhiro Maeshima, Saera Hihara and Mikhail Eltsov Current Opinion in Cell Biology, 22 291-297, 2010. doi:10.1016/j.ceb.2010.03.001 A long strand of DNA is wrapped around the core histone and forms a nucleosome. Although the nucleosome has long been assumed to be folded into 30-nm chromatin fibres, their structural details and how such fibres are organised into a nucleus or mitotic chromosome remain unclear. When we observed frozen hydrated (vitrified) human mitotic cells using cryo-electron microscopy, which enables direct high- resolution imaging of the cellular structures in a close-to-native state, we found no higher order structures including 30-nm chromatin fibres in the chromosome. In this review, we propose that the nucleosome fibres in nuclei or mitotic chromosomes exist in a highly disordered state, which is locally similar to a "polymer melt" with dynamic movements. We assume that this local dynamic movements result in several advantages in the chromosome condensation, transcriptional regulation and DNA replication processes.
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