Self-organization of kinetochore-fibers in human mitotic spindles
- Harvard University, United States
- Technische Universität Dresden, Germany
Abstract
During eukaryotic cell division, chromosomes are linked to microtubules (MTs) in the spindle by a macromolecular complex called the kinetochore. The bound kinetochore microtubules (KMTs) are crucial to ensuring accurate chromosome segregation. Recent reconstructions by electron tomography (Kiewisz et al. 2021) captured the positions and configurations of every MT in human mitotic spindles, revealing that roughly half the KMTs in these spindles do not reach the pole. Here, we investigate the processes that give rise to this distribution of KMTs using a combination of analysis of large-scale electron tomography, photoconversion experiments, quantitative polarized light microscopy, and biophysical modeling. Our results indicate that in metaphase, KMTs grow away from the kinetochores along well-defined trajectories, with the speed of the KMT minus ends continually decreasing as the minus ends approach the pole, implying that longer KMTs grow more slowly than shorter KMTs. The locations of KMT minus ends, and the turnover and movements of tubulin in KMTs, are consistent with models in which KMTs predominately nucleate de novo at kinetochores in metaphase and are inconsistent with substantial numbers of non-KMTs being recruited to the kinetochore in metaphase. Taken together, this work leads to a mathematical model of the self-organization of kinetochore-fibers in human mitotic spindles.
Data availability
Source code and data for all figures is uploaded to Github
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Self-organization of kinetochore-fibers in human mitotic spindlesDryad Digital Repository, doi:10.5061/dryad.69p8cz948.
Article and author information
Author details
Thomas Müller-Reichert
Funding
NSF-Simons Foundation (Center for Mathematical and Statistical Analysis of Biology at Harvard,1764269)
- William Conway
- Colm P Kelleher
- Hai-Yin Wu
- Maya Anjur-Dietrich
- Daniel J Needleman
NSF (Graduate Research Fellowship Program)
- William Conway
Deutsche Forsschunggemeinshaft (MU 1423/8-2)
- Robert Kiewisz
- Gunar Fabig
- Thomas Müller-Reichert
European Union Horizon (Marie Sklodowska-Curie Agreement,675737)
- Robert Kiewisz
- Thomas Müller-Reichert
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Copyright
© 2022, Conway et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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