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Updated: Oct 3, 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

MTOC formation during mitotic exit in fission yeast

M J Heitz1, J Petersen, S Valovin

  • 1School of Biological Sciences, 2.205 Stopford Building, University of Manchester, Stopford Building, Oxford Road, Manchester M13 9PT, UK.

Journal of Cell Science
|January 17, 2002
PubMed

Insights

The equatorial microtubule organizing center (MTOC) in fission yeast forms from gamma tubulin recruited to the F-actin ring during cell division. Its assembly requires the septation-inducing network and polo-like kinase, Plo1.

Area of Science:

  • Cell Biology
  • Cytoskeleton Dynamics
  • Molecular Cell Biology

Background:

  • Microtubules polymerize from nucleation templates containing gamma tubulin.
  • Microtubule organizing centers (MTOCs) concentrate these templates.
  • In Schizosaccharomyces pombe, an equatorial MTOC (EMTOC) forms during anaphase B and disassembles during cell separation.

Purpose of the Study:

  • To investigate the formation and regulation of the equatorial MTOC during cytokinesis in Schizosaccharomyces pombe.
  • To elucidate the relationship between the F-actin ring, the septation-inducing network (SIN), and MTOC assembly.

Main Methods:

  • Recruitment of gamma tubulin to the equatorial F-actin ring.
  • Analysis of EMTOC structure and integrity.
  • Investigating the roles of the SIN and anaphase-promoting complex in EMTOC assembly.
  • Examining the effect of Plo1 overproduction on EMTOC formation.

Main Results:

  • The EMTOC is generated by recruiting gamma tubulin to the equatorial F-actin ring prior to cytokinesis.
  • EMTOC structure is variable (horseshoe to bars) and depends on F-actin integrity, not microtubules.
  • EMTOC assembly requires the SIN and anaphase-promoting complex.
  • Plo1 overproduction induces EMTOC formation, suggesting a role in mitotic exit.

Conclusions:

  • The equatorial MTOC formation is linked to F-actin ring constriction during cytokinesis.
  • EMTOC assembly involves regulatory elements of cytokinesis but is more complex.
  • Plo1 has an additional function in mitotic exit related to EMTOC formation.

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