Human mitotic chromosomes consist predominantly of irregularly folded nucleosome fibres without a 30-nm chromatin structure

Yoshinori Nishino, Mikhail Eltsov, Yasumasa Joti, Kazuki Ito, Hideaki Takata, Yukio Takahashi, Saera Hihara, Achilleas S. Frangakis, Naoko Imamoto, Tetsuya Ishikawa, Kazuhiro Maeshima

Research output: Contribution to journalArticlepeer-review

221 Citations (Scopus)

Abstract

How a long strand of genomic DNA is compacted into a mitotic chromosome remains one of the basic questions in biology. The nucleosome fibre, in which DNA is wrapped around core histones, has long been assumed to be folded into a 30-nm chromatin fibre and further hierarchical regular structures to form mitotic chromosomes, although the actual existence of these regular structures is controversial. Here, we show that human mitotic HeLa chromosomes are mainly composed of irregularly folded nucleosome fibres rather than 30-nm chromatin fibres. Our comprehensive and quantitative study using cryo-electron microscopy and synchrotron X-ray scattering resolved the long-standing contradictions regarding the existence of 30-nm chromatin structures and detected no regular structure >11 nm. Our finding suggests that the mitotic chromosome consists of irregularly arranged nucleosome fibres, with a fractal nature, which permits a more dynamic and flexible genome organization than would be allowed by static regular structures.

Original languageEnglish
Pages (from-to)1644-1653
Number of pages10
JournalEMBO Journal
Volume31
Issue number7
DOIs
Publication statusPublished - 2012 Apr 4
Externally publishedYes

Keywords

  • 30-nm chromatin fibre
  • Chromosome structure
  • X-ray sacattering
  • cryo-EM
  • fractal structure

ASJC Scopus subject areas

  • Neuroscience(all)
  • Molecular Biology
  • Biochemistry, Genetics and Molecular Biology(all)
  • Immunology and Microbiology(all)

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