Systematic identification of factors bound to isolated metaphase ESC chromosomes reveals a role for chromatin repressors in compaction
Dounia Djeghloul, Anne-Céline Kohler, Bhavik Patel, Holger Kramer, Nicolas Veland, Chad Whilding, Andrew Dimond, James Elliott, Amelie Feytout, Tanmay A.M. Bharat, Abul K. Tarafder, Jan Löwe, Bee L. Ng, Ya Guo, Karen Brown, Jacky Guy, Matthias Merkenschlager and Amanda G. Fisher
Received Date: 20th August 19
Epigenetic information is transmitted from mother to daughter cells through mitosis. To identify trans-acting factors and cis-acting elements that might be important for conveying epigenetic memory through cell division, we isolated native (unfixed) chromosomes from metaphase-arrested cells using flow cytometry and performed LC-MS/MS to determine the repertoire of chromosome-bound proteins. Quantitative proteomic comparisons between metaphase-arrested cell lysates and chromosome-sorted samples revealed a cohort of proteins that were significantly enriched on mitotic ESC chromosomes. These include pluripotency-associated transcription factors, repressive chromatin-modifiers (such as PRC2 and DNA methyl-transferases) and proteins governing chromosome architecture. We showed that deletion of PRC2, DNMT1/3a/3b or Mecp2 provoked an increase in the size of individual mitotic chromosomes consistent with de-condensation, as did experimental cleavage of cohesin complexes. These data provide a comprehensive inventory of chromosome-bound factors in pluripotent stem cells at mitosis and reveal an unexpected role for chromatin repressor complexes in preserving mitotic chromosome compaction.
Read in full at bioRxiv.
This is an abstract of a preprint hosted on an independent third party site. It has not been peer reviewed but is currently under consideration at Nature Communications.