Structure of the human inner kinetochore bound to a centromeric CENP-A nucleosome

Yatskevich, S.; Muir, K. W.; Bellini, D.; Zhang, Z.; Yang, J.; Tischer, T.; Predin, M.; Dendooven, T.; McLaughlin, S. H.; Barford, D.

doi:10.1101/2022.01.07.475394

bioRxiv · 10.1101/2022.01.07.475394

Structure of the human inner kinetochore bound to a centromeric CENP-A nucleosome

Yatskevich, S.·Muir, K. W.·Bellini, D.·Zhang, Z.·Yang, J.·Tischer, T.·Predin, M.·Dendooven, T.·McLaughlin, S. H.·Barford, D.

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Abstract

Accurate chromosome segregation, controlled by kinetochore-mediated chromatid attachments to the mitotic spindle, ensures the faithful inheritance of genetic information. Kinetochores assemble onto specialized CENP-A nucleosomes (CENP-ANuc) of centromeric chromatin. In humans, this is mostly organized as thousands of copies of an [~]171 bp -satellite repeat. Here, we describe the cryo-EM structure of the human inner kinetochore CCAN (Constitutive Centromere Associated Network) complex bound to CENP-ANuc reconstituted onto -satellite DNA. CCAN forms edge-on contacts with CENP-ANuc, while a linker DNA segment of the -satellite repeat emerges from the fully-wrapped end of the nucleosome to thread through the central CENP-LN channel which tightly grips the DNA. The CENP-TWSX histone-fold module, together with CENP-HIKHead, further augments DNA binding and partially wraps the linker DNA in a manner reminiscent of canonical nucleosomes. Our study suggests that the topological entrapment of the -satellite repeat linker DNA by CCAN provides a robust mechanism by which the kinetochore withstands the pushing and pulling of centromeres associated with chromosome congression and segregation forces. One-Sentence SummaryThe human inner kinetochore CCAN complex tightly grips the linker DNA of the -satellite CENP-A nucleosome.

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Yatskevich, S., Muir, K. W., Bellini, D., Zhang, Z., Yang, J., Tischer, T., Predin, M., Dendooven, T., McLaughlin, S. H., Barford, D.. 2022-01-08. Structure of the human inner kinetochore bound to a centromeric CENP-A nucleosome. https://doi.org/10.1101/2022.01.07.475394

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