Microneedle manipulation of the mammalian spindle reveals specialized, short-lived reinforcement near chromosomes
Abstract
The spindle generates force to segregate chromosomes at cell division. In mammalian cells, kinetochore-fibers connect chromosomes to the spindle. The dynamic spindle anchors kinetochore-fibers in space and time to move chromosomes. Yet, how it does so remains poorly understood as we lack tools to directly challenge this anchorage. Here, we adapt microneedle manipulation to exert local forces on the spindle with spatiotemporal control. Pulling on kinetochore-fibers reveals the preservation of local architecture in the spindle-center over seconds. Sister, but not neighbor, kinetochore-fibers remain tightly coupled, restricting chromosome stretching. Further, pulled kinetochore-fibers pivot around poles but not chromosomes, retaining their orientation within 3 μm of chromosomes. This local reinforcement has a 20 s lifetime, and requires the microtubule crosslinker PRC1. Together, these observations indicate short-lived, specialized reinforcement in the spindle center. This could help protect chromosome attachments from transient forces while allowing spindle remodeling, and chromosome movements, over longer timescales.
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Funding
National Institute of General Medical Sciences (DP2GM119177)
- Sophie Dumont
National Institute of General Medical Sciences (1R01GM134132)
- Sophie Dumont
National Science Foundation (1554139 CAREER)
- Sophie Dumont
National Science Foundation (1548297 Center for Cellular Construction)
- Sophie Dumont
Rita Allen Foundation
- Sophie Dumont
Chicago Community Trust (Searle Scholars' Program)
- Sophie Dumont
National Science Foundation (Graduate Research Fellowship)
- Pooja Suresh
- Alexandra F Long
University of California, San Francisco (UCSF Kozloff Fellowship)
- Alexandra F Long
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Copyright
© 2020, Suresh 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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