Methylated histones on mitotic chromosomes promote topoisomerase IIα function for high fidelity chromosome segregation

Autor: Sanjana Sundararajan, Hyewon Park, Shinji Kawano, Marnie Johansson, Bunu Lama, Tomoko Saito-Fujita, Noriko Saitoh, Alexei Arnaoutov, Mary Dasso, Zhengqiang Wang, Daniel Keifenheim, Duncan J. Clarke, Yoshiaki Azuma
Jazyk: angličtina
Rok vydání: 2023
Předmět:
Zdroj: iScience, Vol 26, Iss 5, Pp 106743- (2023)
Druh dokumentu: article
ISSN: 2589-0042
DOI: 10.1016/j.isci.2023.106743
Popis: Summary: DNA Topoisomerase IIα (TopoIIα) decatenates sister chromatids, allowing their segregation in mitosis. Without the TopoIIα Strand Passage Reaction (SPR), chromosome bridges and ultra-fine DNA bridges (UFBs) arise in anaphase. The TopoIIα C-terminal domain is dispensable for the SPR in vitro but essential for mitotic functions in vivo. Here, we present evidence that the Chromatin Tether (ChT) within the CTD interacts with specific methylated nucleosomes and is crucial for high-fidelity chromosome segregation. Mutation of individual αChT residues disrupts αChT-nucleosome interaction, induces loss of segregation fidelity and reduces association of TopoIIα with chromosomes. Specific methyltransferase inhibitors reducing histone H3 or H4 methylation decreased TopoIIα at centromeres and increased segregation errors. Methyltransferase inhibition did not further increase aberrant anaphases in the ChT mutants, indicating a functional connection. The evidence reveals novel cellular regulation whereby TopoIIα specifically interacts with methylated nucleosomes via the αChT to ensure high-fidelity chromosome segregation.
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