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Updated: May 31, 2026

Self-Assembly of Microtubule Tactoids
Published on: June 23, 2022
Microtubule assembly in meiotic extract requires glycogen
Aaron C Groen1, Margaret Coughlin, Timothy J Mitchison
1Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA. aaron_groen@hms.harvard.edu
Abstract:
The assembly of microtubules during mitosis requires many identified components, such as γ-tubulin ring complex (γ-TuRC), components of the Ran pathway (e.g., TPX2, HuRP, and Rae1), and XMAP215/chTOG. However, it is far from clear how these factors function together or whether more factors exist. In this study, we used biochemistry to attempt to identify active microtubule nucleation protein complexes from Xenopus meiotic egg extracts. Unexpectedly, we found both microtubule assembly and bipolar spindle assembly required glycogen, which acted both as a crowding agent and as metabolic source glucose. By also reconstituting microtubule assembly in clarified extracts, we showed microtubule assembly does not require ribosomes, mitochondria, or membranes. Our clarified extracts will provide a powerful tool for activity-based biochemical fractionations for microtubule assembly.
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