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Microtubules and Alp7-Alp14 (TACC-TOG) reposition chromosomes before meiotic segregation

Yasutaka Kakui1, Masamitsu Sato, Naoyuki Okada

  • 1Department of Biophysics and Biochemistry, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Tokyo 113-0032, Japan.

Nature Cell Biology
|June 18, 2013
PubMed

Insights

Fission yeast prevents chromosome mis-segregation during meiosis by assembling microtubule arrays that capture scattered kinetochores. A specific protein complex (Alp7-Alp14) aids this capture, ensuring proper chromosome configuration.

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Genetics

Background:

  • During yeast meiosis, kinetochores detach from spindle poles to promote recombination, risking chromosome mis-segregation.
  • The mechanism by which cells prevent mis-segregation despite detached kinetochores remains unclear.

Purpose of the Study:

  • To investigate how fission yeast prevents chromosome mis-segregation during meiosis despite kinetochore detachment.
  • To elucidate the role of microtubule dynamics and associated proteins in maintaining chromosome integrity during meiosis.

Main Methods:

  • Microscopy to observe microtubule assembly and kinetochore positioning.
  • Biochemical assays to study protein interactions and phosphorylation.
  • Genetic analysis of mutant strains lacking key proteins.

Main Results:

  • An extensive microtubule array forms at meiosis I onset, retrieving scattered kinetochores towards spindle poles.
  • Phosphorylation of the Alp7-Alp14 complex by Polo kinase promotes its association with Nuf2-Ndc80 kinetochores, aiding capture.
  • Dis1 and the Dam1 complex contribute to microtubule shortening, pulling kinetochores poleward.

Conclusions:

  • Fission yeast employs a unique strategy involving microtubule dynamics and specific protein complexes to ensure accurate chromosome segregation during meiosis.
  • The study reveals a novel role for the Alp7-Alp14 complex in kinetochore capture during meiosis.

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