2025-08-20 理化学研究所,九州大学
マウス卵母細胞における染色体の両方向性の確立におけるKIF11の空間的な必要量の違い
<関連情報>
- https://www.riken.jp/press/2025/20250820_2/index.html
- https://www.embopress.org/doi/full/10.1038/s44319-025-00539-w
Kif11半欠損卵母細胞は染色体二極化に空間的に異なる要件を示す Kif11-haploinsufficient oocytes reveal spatially differential requirements for chromosome biorientation
Tappei Mishina, Aurélien Courtois, Shuhei Yoshida, Kohei Asai, Hiroshi Kiyonari, and Tomoya S Kitajima,
EMBO Reports Published:20 August 2025
DOI:https://doi.org/10.1038/s44319-025-00539-w
Abstract
Bipolar spindle assembly and chromosome biorientation are prerequisites for chromosome segregation during cell division. The kinesin motor KIF11 (also widely known as Eg5) drives spindle bipolarization by sliding antiparallel microtubules bidirectionally, elongating a spherical spindle into a bipolar-shaped structure in acentrosomal oocytes. During meiosis I, this process stretches homologous chromosome pairs, establishing chromosome biorientation at the spindle equator. The quantitative requirement for KIF11 in acentrosomal spindle bipolarization and homologous chromosome biorientation remains unclear. Here, using a genetic strategy to modulate KIF11 expression levels, we show that Kif11 haploinsufficiency impairs spindle elongation, leading to the formation of a partially bipolarized spindle during meiosis I in mouse oocytes. While the partially bipolarized spindle allows chromosome stretching in the inner region of its equator, it fails to do so in the outer region, where merotelic kinetochore-microtubule attachments are favored to form. These findings demonstrate the necessity of biallelic functional Kif11 for bipolar spindle assembly in acentrosomal oocytes and reveal a spatially differential requirement for homologous chromosome biorientation within the spindle.
Synopsis
This study reveals the necessity of biallelic functional Kif11 for bipolar spindle assembly in acentrosomal oocytes and a spatially differential requirement for homologous chromosome biorientation within the spindle.
- Haploinsufficiency of Kif11 causes spindle assembly defects in mouse oocytes.
- Partially bipolarized spindles in Kif11-haploinsufficient oocytes allow chromosome biorientation in the inner region of the equator, but not in the outer region.
- Merotelic kinetochore-microtubule attachment is more likely to form in the outer region.
- Requirement of KIF11 dosage for chromosome biorientation differs spatially in the oocyte spindle.
