Kinetochore-independent chromosome segregation driven by lateral microtubule bundles

Abstract
Article and author information
Metrics

Abstract

During cell division, chromosomes attach to spindle microtubules at sites called kinetochores, and force generated at the kinetochore-microtubule interface is the main driver of chromosome movement. Surprisingly, kinetochores are not required for chromosome segregation on acentrosomal spindles in C. elegans oocytes, but the mechanism driving chromosomes apart in their absence is not understood. Here we show that lateral microtubule-chromosome associations established during prometaphase remain intact during anaphase to facilitate separation, defining a novel form of kinetochore-independent segregation. Chromosome dynamics during congression and segregation are controlled by opposing forces; plus-end directed forces are mediated by a protein complex that forms a ring around the chromosome center and dynein on chromosome arms provides a minus-end force. At anaphase onset, ring removal shifts the balance between these forces, triggering poleward movement along lateral microtubule bundles. This represents an elegant strategy for controlling chromosomal movements during cell division distinct from the canonical kinetochore-driven mechanism.

Article and author information

Author details

Christina C Muscat

Department of Molecular Biosciences, Northwestern University, Evanston, United States

Competing interests
The authors declare that no competing interests exist.
Keila M Torre-Santiago

Department of Molecular Biosciences, Northwestern University, Evanston, United States

Competing interests
The authors declare that no competing interests exist.
Michael V Tran

Department of Molecular Biosciences, Northwestern University, Evanston, United States

Competing interests
The authors declare that no competing interests exist.
James A Powers

Light Microscopy Imaging Center, Indiana University, Bloomington, United States

Competing interests
The authors declare that no competing interests exist.
Sarah M Wignall

Department of Molecular Biosciences, Northwestern University, Evanston, United States

For correspondence
s-wignall@northwestern.edu

Competing interests
The authors declare that no competing interests exist.

Copyright

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.