XB-ART-53845Science 2017 Jun 23;3566344:1284-1287. doi: 10.1126/science.aam9702.
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Mitotic chromosome assembly despite nucleosome depletion in Xenopus egg extracts.
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.
PubMed ID: 28522692
Article link: Science
Species referenced: Xenopus laevis
Genes referenced: asf1a
Kakui, Building chromosomes without bricks. 2017, Pubmed