Kinetochore-mediated outward force promotes spindle pole separation in fission yeast

Yutaka Shirasugi, Masamitsu Sato

Research output: Contribution to journalArticle

Abstract

Bipolar spindles are organized by motor proteins that generate microtubule--dependent forces to separate the two spindle poles. The fission yeast Cut7 (kinesin-5) is a plus-end-directed motor that generates the outward force to separate the two spindle poles, whereas the minus-end-directed motor Pkl1 (kinesin-14) generates the inward force. Balanced forces by these antagonizing kinesins are essential for bipolar spindle organization in mitosis. Here, we demonstrate that chromosomes generate another outward force that contributes to the bipolar spindle assembly. First, it was noted that the cut7 pkl1 double knockout failed to separate spindle poles in meiosis I, although the mutant is known to succeed it in mitosis. It was assumed that this might be because meiotic kinetochores of bivalent chromosomes joined by cross-overs generate weaker tensions in meiosis I than the strong tensions in mitosis generated by tightly tethered sister kinetochores. In line with this idea, when meiotic mono-oriented kinetochores were artificially converted to a mitotic bioriented layout, the cut7 pkl1 mutant successfully separated spindle poles in meiosis I. Therefore, we propose that spindle pole separation is promoted by outward forces transmitted from kinetochores to spindle poles through microtubules.

Original languageEnglish
Pages (from-to)2802-2813
Number of pages12
JournalMolecular biology of the cell
Volume30
Issue number22
DOIs
Publication statusPublished - 2019 Oct 15

ASJC Scopus subject areas

  • Molecular Biology
  • Cell Biology

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