Kinetochore fibers are not involved in the formation of the first meiotic spindle in mouse oocytes, but control the exit from the first meiotic M phase
Kinetochore fibers are not involved in the formation of the first meiotic spindle in mouse oocytes, but control the exit from the first meiotic M phase
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DOI：
10.1083/jcb.146.1.1
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发表时间：
1999-07-12
影响因子：
7.8
通讯作者：
Maro, B
中科院分区：
文献类型：
--
作者：
Brunet, S;Maria, AS;Maro, B
在减数分裂过程中，连续发生两次分裂，没有任何中间的S阶段产生单倍体配子。第一次减数分裂的独特之处在于，同源染色体被分离，而姐妹染色单体之间的凝聚力保持不变，导致减数分裂。此外，在小鼠卵母细胞中，第一次减数分裂M期的持续时间通常比有丝分裂M期长8小时。我们研究了纺锤体组装途径及其在小鼠卵母细胞第一次减数分裂M期进展中的作用。在最初的4h内，形成一个两极纺锤体，染色体在纺锤体的赤道面附近弯曲，没有稳定的动粒-微管末端相互作用。这个早中期晚期的纺锤体维持4h，染色体在纺锤体的中心区振荡。动粒-微管末端相互作用在第一次减数分裂M期结束时(进入M期后8h)建立。这一事件允许染色体的最终对齐并退出中期。前中期纺锤体的持续存在不是第一次减数分裂M期进行所必需的。最后，动点与微管相互作用的能力是在第一次减数分裂M期结束时获得的，并决定了极体挤出的时间。
During meiosis, two successive divisions occur without any intermediate S phase to produce haploid gametes. The first meiotic division is unique in that homologous chromosomes are segregated while the cohesion between sister chromatids is maintained, resulting in a reductional division. Moreover, the duration of the first meiotic M phase is usually prolonged when compared with mitotic M phases lasting 8 h in mouse oocytes.We investigated the spindle assembly pathway and its role in the progression of the first meiotic M phase In mouse oocytes. During the first 4 h, a bipolar spindle forms and the chromosomes congress near the equatorial plane of the spindle without stable kinetochore-microtubule end interactions. This late prometaphase spindle is then maintained for 4 h with chromosomes oscillating in the central region of the spindle. The kinetochore-microtubule end interactions are set up at the end of the first meiotic M phase (8 h after entry into M phase). This event allows the final alignment of the chromosomes and exit from metaphase. The continuous presence of the prometaphase spindle is not required for progression of the first meiotic M phase. Finally, the ability of kinetochores to interact with microtubules is acquired at the end of the first meiotic M phase and determines the timing of polar body extrusion.