Mitotic chromosome assembly despite nucleosome depletion in Xenopus egg extracts

作者:Shintomi Keishi; Inoue Fukashi; Watanabe Hiroshi; Ohsumi Keita; Ohsugi Miho; Hirano Tatsuya*
来源:Science, 2017, 356(6344): 1284-1287.
DOI:10.1126/science.aam9702

摘要

The nucleosome is the fundamental structural unit of eukaryotic chromatin. During mitosis, duplicated nucleosome fibers are organized into a pair of rod-shaped structures (chromatids) within a mitotic chromosome. However, it remains unclear whether nucleosome assembly is indeed an essential prerequisite for mitotic chromosome assembly. We combined mouse sperm nuclei and Xenopus cell-free egg extracts depleted of the histone chaperone Asf1 and found that chromatid-like structures could be assembled even in the near absence of nucleosomes. The resultant "nucleosome-depleted" chromatids contained discrete central axes positive for condensins, although they were more fragile than normal nucleosome-containing chromatids. Combinatorial depletion experiments underscored the central importance of condensins in mitotic chromosome assembly, which sheds light on their functional cross-talk with nucleosomes in this process.

  • 出版日期2017-6-23