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Updated: Mar 6, 2026

Directly Measuring Forces Within Reconstituted Active Microtubule Bundles
Published on: May 10, 2022
Stepwise unfolding supports a subunit model for vertebrate kinetochores
Giulia Vargiu1, Alexandr A Makarov1, James Allan2
1Wellcome Trust Centre for Cell Biology, University of Edinburgh, Edinburgh EH9 3BF, Scotland, United Kingdom.
Abstract:
During cell division, interactions between microtubules and chromosomes are mediated by the kinetochore, a proteinaceous structure located at the primary constriction of chromosomes. In addition to the centromere histone centromere protein A (CENP-A), 15 other members of the constitutive centromere associated network (CCAN) participate in the formation of a chromatin-associated scaffold that supports kinetochore structure. We performed a targeted screen analyzing unfolded centrochromatin from CENP-depleted chromosomes. Our results revealed that CENP-C and CENP-S are critical for the stable folding of mitotic kinetochore chromatin. Multipeak fitting algorithms revealed the presence of an organized pattern of centrochromatin packing consistent with arrangement of CENP-A-containing nucleosomes into up to five chromatin "subunits"-each containing roughly 20-30 nucleosomes. These subunits could be either layers of a boustrophedon or small loops of centromeric chromatin.
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