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Updated: Aug 15, 2026

Examination of Mitotic and Meiotic Fission Yeast Nuclear Dynamics by Fluorescence Live-cell Microscopy
12:04

Examination of Mitotic and Meiotic Fission Yeast Nuclear Dynamics by Fluorescence Live-cell Microscopy

Published on: June 24, 2019

Mal3, the fission yeast EB1 homologue, cooperates with Bub1 spindle checkpoint to prevent monopolar attachment

Kazuhide Asakawa1, Mika Toya, Masamitsu Sato

  • 1Laboratory of Cell Regulation, Cancer Research UK, London Research Institute, Lincoln's Inn Fields Laboratories, 44 Lincoln's Inn Fields, London WC2A 3PX, UK.

EMBO Reports
|September 24, 2005
PubMed

Insights

The fission yeast protein Mal3 prevents chromosome mis-segregation by ensuring bipolar microtubule attachment. Its absence delays mitosis and causes defects in cooperation with the Bub1 spindle checkpoint.

Area of Science:

  • Cell Biology
  • Genetics
  • Molecular Biology

Background:

  • Bipolar microtubule attachment is crucial for accurate chromosome segregation during mitosis, maintaining genome stability.
  • The EB1 family of microtubule-associated proteins plays roles in microtubule dynamics and spindle organization.
  • Fission yeast provides a model system to study fundamental cell division processes.

Purpose of the Study:

  • To investigate the role of the fission yeast EB1 homologue, Mal3, during mitosis.
  • To determine Mal3's contribution to spindle assembly and chromosome segregation.
  • To elucidate the relationship between Mal3 and spindle assembly checkpoint proteins.

Main Methods:

  • Analysis of Mal3 localization and dynamics during mitosis in fission yeast.
  • Creation and phenotypic analysis of Mal3 deletion mutants and double mutants with spindle checkpoint components (e.g., bub1, mad2).
  • Microscopy techniques to observe microtubule attachment, kinetochore localization, and chromosome segregation.

Main Results:

  • Mal3 exhibits dynamic movement along the spindle, originating from the spindle pole body (SPB) and moving towards the equatorial plane.
  • Deletion of Mal3 leads to an early mitotic delay dependent on Bub1, but not Mad2.
  • Mal3 deletion mutants, especially in combination with bub1, bub3, mad3, or mph1, display significant chromosome mis-segregation, with centromeres often attached to only one SPB.

Conclusions:

  • Mal3 is essential for preventing monopolar microtubule attachment during mitosis.
  • Mal3 functions in concert with the Bub1/Bub3/Mad3/Mph1 spindle assembly checkpoint pathway.
  • Proper Mal3 function and its interaction with checkpoint proteins are vital for accurate chromosome segregation and genome stability.

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