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Stable kinetochore-microtubule attachments restrict MTOC position and spindle elongation in oocytes

Aurélien Courtois1, Shuhei Yoshida1, Osamu Takenouchi1

  • 1Laboratory for Chromosome Segregation, RIKEN Center for Biosystems Dynamics Research (BDR), Kobe, Japan.

EMBO Reports
|March 3, 2021
PubMed

Insights

Stable kinetochore-microtubule attachments are crucial for organizing microtubule organizing centers (MTOCs) during spindle bipolarization in mouse oocytes. Disrupting these attachments prevents proper spindle formation and elongation control.

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Developmental Biology

Background:

  • Acentriolar microtubule organizing centers (MTOCs) in mouse oocytes replace centrosomes for microtubule nucleation.
  • Spindle bipolarization, the formation of a bipolar spindle from nucleated microtubules, is essential for cell division.
  • Kinetochores promote spindle bipolarization, but the precise role of kinetochore-microtubule attachments is not fully understood.

Purpose of the Study:

  • To investigate the mechanism by which kinetochore-microtubule attachments contribute to spindle bipolarity in mouse oocytes.
  • To determine the role of stable kinetochore-microtubule attachments in MTOC positioning and spindle elongation.

Main Methods:

  • Live-cell imaging of microtubules and MTOCs in mouse oocytes.
  • Perturbation of kinetochore-microtubule attachments using chemical inhibitors or genetic manipulation.
  • Analysis of spindle morphology, MTOC localization, and spindle length.

Main Results:

  • The stability of kinetochore-microtubule attachments is essential for confining MTOCs to spindle poles.
  • Disruption of stable attachments leads to uncontrolled spindle elongation and failure to restrict MTOCs.
  • MTOC sorting is a gradual process that persists into metaphase, regulated by stable kinetochore fibers.

Conclusions:

  • Stable kinetochore-microtubule attachments play a critical role in regulating acentrosomal spindle bipolarity by controlling MTOC positioning and spindle length.
  • These attachments act as crucial regulators, ensuring proper spindle organization and termination of elongation in the absence of centrosomes.
Keywords:
MTOCkinetochoremicrotubuleoocytespindle

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