Co-movement of astral microtubules, organelles and F-actin by dynein and actomyosin forces in frog egg cytoplasm

  1. James F Pelletier
  2. Christine M. Field
  3. Sebastian Fuerthauer
  4. Matthew Sonnett
  5. Timothy J Mitchison  Is a corresponding author
  1. Harvard Medical School, United States
  2. Flatiron Institute, United States

Abstract

How bulk cytoplasm generates forces to separate post-anaphase microtubule (MT) asters in Xenopus laevis and other large eggs remains unclear. Previous models proposed that dynein-based, inward organelle transport generates length-dependent pulling forces that move centrosomes and MTs outwards while other components of cytoplasm are static. We imaged aster movement by dynein and actomyosin forces in Xenopus egg extracts and observed outward co-movement of MTs, endoplasmic reticulum (ER), mitochondria, acidic organelles, F-actin, keratin and soluble fluorescein. Organelles exhibited a burst of dynein-dependent inward movement at the growing aster periphery, then mostly halted inside the aster, while dynein-coated beads moved to the aster center at a constant rate, suggesting organelle movement is limited by brake proteins or other sources of drag. These observations call for new models in which all components of the cytoplasm comprise a mechanically integrated aster gel that moves collectively in response to dynein and actomyosin forces.

Data availability

All data generated or analyzed during this study are included in the manuscript and supporting files. We are in the process of uploading the source data and code to GitHub https://github.com/jamespelletier/Co-movement

Article and author information

Author details

  1. James F Pelletier

    Department of Systems Biology, Harvard Medical School, Boston, United States
    Competing interests
    The authors declare that no competing interests exist.
  2. Christine M. Field

    Department of Systems Biology, Harvard Medical School, Boston, United States
    Competing interests
    The authors declare that no competing interests exist.
  3. Sebastian Fuerthauer

    Center for Computational Biology, Flatiron Institute, New York, United States
    Competing interests
    The authors declare that no competing interests exist.
  4. Matthew Sonnett

    Department of Systems Biology, Harvard Medical School, Boston, United States
    Competing interests
    The authors declare that no competing interests exist.
  5. Timothy J Mitchison

    Department of Systems Biology, Harvard Medical School, Boston, United States
    For correspondence
    Timothy_Mitchison@hms.harvard.edu
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0001-7781-1897

Funding

National Institute of General Medical Sciences (R35GM131753)

  • Timothy J Mitchison

Hertz Foundation

  • James F Pelletier

The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.

Reviewing Editor

  1. Thomas Surrey, Centre for Genomic Regulation (CRG), Spain

Ethics

Animal experimentation: This study was performed in strict accordance with the recommendations in the Guide for the Care and Use of Laboratory Animals of the National Institutes of Health. All of the animals were handled according to approved institutional animal care and use committee (IACUC) protocols (#IS00000519-3) of Harvard Medical School. The institution has an approved Animal Welfare Assurance on file with the Office of Laboratory Animal Welfare. The Assurance number on file is #D16-00270.

Version history

  1. Received: June 15, 2020
  2. Accepted: December 5, 2020
  3. Accepted Manuscript published: December 7, 2020 (version 1)
  4. Version of Record published: December 24, 2020 (version 2)

Copyright

© 2020, Pelletier 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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  1. James F Pelletier
  2. Christine M. Field
  3. Sebastian Fuerthauer
  4. Matthew Sonnett
  5. Timothy J Mitchison
(2020)
Co-movement of astral microtubules, organelles and F-actin by dynein and actomyosin forces in frog egg cytoplasm
eLife 9:e60047.
https://doi.org/10.7554/eLife.60047

Share this article

https://doi.org/10.7554/eLife.60047

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