Program in Systems Biology; Department of Biochemistry and Molecular Pharmacology
Amino Acids, Peptides, and Proteins | Biochemistry | Cell Biology | Genetics and Genomics | Structural Biology | Systems Biology
During mitosis chromosomes reorganise into highly compact, rod-shaped forms, thought to consist of consecutive chromatin loops around a central protein scaffold. Condensin complexes are involved in chromatin compaction, but the contribution of other chromatin proteins, DNA sequence and histone modifications is less understood. A large region of fission yeast DNA inserted into a mouse chromosome was previously observed to adopt a mitotic organisation distinct from that of surrounding mouse DNA. Here, we show that a similar distinct structure is common to a large subset of insertion events in both mouse and human cells and is coincident with the presence of high levels of heterochromatic H3 lysine nine trimethylation (H3K9me3). Hi-C and microscopy indicate that the heterochromatinised fission yeast DNA is organised into smaller chromatin loops than flanking euchromatic mouse chromatin. We conclude that heterochromatin alters chromatin loop size, thus contributing to the distinct appearance of heterochromatin on mitotic chromosomes.
S. pombe, cell biology, chromosome structure, chromosomes, condensin, gene expression, heterochromatin, human, loop extrusion, mouse
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© 2020, Fitz-James et al. This article is distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use and redistribution provided that the original author and source are credited.
DOI of Published Version
Fitz-James MH, Tong P, Pidoux AL, Ozadam H, Yang L, White SA, Dekker J, Allshire RC. Large domains of heterochromatin direct the formation of short mitotic chromosome loops. Elife. 2020 Sep 11;9:e57212. doi: 10.7554/eLife.57212. PMID: 32915140; PMCID: PMC7515631. Link to article on publisher's site
Fitz-James MH, Tong P, Pidoux AL, Ozadam H, Yang L, White SA, Dekker J, Allshire RC. (2020). Large domains of heterochromatin direct the formation of short mitotic chromosome loops. Open Access Articles. https://doi.org/10.7554/eLife.57212. Retrieved from https://escholarship.umassmed.edu/oapubs/4355
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