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XB-ART-58313
Elife August 18, 2021; 10
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Linker histone H1.8 inhibits chromatin binding of condensins and DNA topoisomerase II to tune chromosome length and individualization.

Choppakatla P , Dekker B , Cutts EE , Vannini A , Dekker J , Funabiki H .


Abstract
DNA loop extrusion by condensins and decatenation by DNA topoisomerase II (topo II) are thought to drive mitotic chromosome compaction and individualization. Here, we reveal that the linker histone H1.8 antagonizes condensins and topo II to shape mitotic chromosome organization. In vitro chromatin reconstitution experiments demonstrate that H1.8 inhibits binding of condensins and topo II to nucleosome arrays. Accordingly, H1.8 depletion in Xenopus egg extracts increased condensins and topo II levels on mitotic chromatin. Chromosome morphology and Hi-C analyses suggest that H1.8 depletion makes chromosomes thinner and longer through shortening the average loop size and reducing the DNA amount in each layer of mitotic loops. Furthermore, excess loading of condensins and topo II to chromosomes by H1.8 depletion causes hyper-chromosome individualization and dispersion. We propose that condensins and topo II are essential for chromosome individualization, but their functions are tuned by the linker histone to keep chromosomes together until anaphase.

PubMed ID: 34406118
PMC ID: PMC8416026
Article link: Elife
Grant support: [+]

Species referenced: Xenopus laevis
Genes referenced: capg frzb2 h2bc21 rho top2a
GO keywords: condensin complex [+]
Antibodies: H3f3a Ab33 Histone H2B Ab10 Ncapd3 Ab1 Tuba4b Ab2

GEO Series: GSE164434: NCBI

Article Images: [+] show captions
References [+] :
Abdennur, Cooler: scalable storage for Hi-C data and other genomically labeled arrays. 2020, Pubmed