Kif2a is a member of the Kinesin-13 microtubule depolymerases. Here, we report the expression, subcellular localization and functions of Kif2a during mouse oocyte meiotic maturation. Immunoblotting analysis showed that Kif2a was gradually increased form GV to the M I stages, and then decreased slightly at the M II stage. Confocal microscopy identified that Kif2a localized to the meiotic spindle, especially concentrated at the spindle poles and inner centromeres in metaphase and translocated to the midbody at telophase. Kif2a depletion by siRNA microinjection generated severely defective spindles and misaligned chromosomes, reduced microtubule depolymerization, which led to significant pro-M I/M Iarrest and failure of first polar body (PB1) extrusion. Kif2a-depleted oocytes were also defective in spindle pole localization of γ-tubulin and showed spindle assembly checkpoint (SAC) protein Bub3 at the kinetochores even after 10 hr extended culture. These results demonstrate that Kif2a may act as a microtubule depolymerase, regulating microtubule dynamics, spindle assembly and chromosome congression, and thus cell cycle progression during mouse oocyte meiotic maturation.
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机译:Kif2a是Kinesin-13微管解聚酶的成员。在这里,我们报告小鼠卵母细胞减数分裂成熟期间Kif2a的表达,亚细胞定位和功能。免疫印迹分析表明,Kif2a从GV逐渐增加到M I期,然后在M II期略有下降。共聚焦显微镜检查发现,Kif2a定位于减数分裂的纺锤体,尤其集中在中期的纺锤体极和内部着丝粒,并在末期转移到中体。通过siRNA显微注射去除Kif2a会产生严重缺陷的纺锤体和染色体错位,减少微管解聚,从而导致显着的Pro-M / I / M-Iarrest和第一极体(PB1)挤出失败。耗尽Kif2a的卵母细胞在γ-微管蛋白的纺锤体极轴定位中也存在缺陷,即使经过10 hr的延长培养后,在动植物中仍显示纺锤体装配检查点(SAC)蛋白Bub3。这些结果表明,Kif2a可以充当微管解聚酶,调节微管动力学,纺锤体组装和染色体聚合,从而调节小鼠卵母细胞减数分裂成熟期间的细胞周期进程。
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