The molecular architecture of the meiotic spindle is remodeled during metaphase arrest in oocytes
The molecular architecture of the meiotic spindle is remodeled during metaphase arrest in oocytes
复制标题
DOI：
10.1083/jcb.201902110
复制
发表时间：
2019-09-01
影响因子：
7.8
通讯作者：
Ohkura, Hiroyuki
中科院分区：
文献类型：
--
作者：
Costa, Mariana F. A.;Ohkura, Hiroyuki
在受精之前，大多数物种的卵母细胞都会经历长期、自然的中期停滞。在此之前，前中期I也被延长，由于后期稳定的着丝粒微管附着。卵母细胞如何在这些时期稳定地维持动态纺锤体数小时还知之甚少。在这里，我们报告的双极纺锤体改变其分子结构在长的前中期/中期I在果蝇卵母细胞。通过产生表达GFP标记的纺锤体蛋白的转基因果蝇，我们发现25种纺锤体蛋白中有14种改变了它们在双极纺锤体中的分布。其中，微管交联的驱动蛋白MKlp 1/Pavarotti和驱动蛋白-5/Klp61F在中期晚期积累到纺锤体赤道。我们发现MKlp 1/Pavarotti的赤道晚期积累受一种与有丝分裂不同的机制调节。虽然MKlp 1/Pavarotti有助于控制纺锤体长度，但驱动蛋白-5/Klp61F对于在中期I停滞期间维持双极纺锤体至关重要。我们的研究提供了新的见解卵母细胞如何维持双极纺锤体在中期阻滞。
Before fertilization, oocytes of most species undergo a long, natural arrest in metaphase. Before this, prometaphase I is also prolonged, due to late stable kinetochore-microtubule attachment. How oocytes stably maintain the dynamic spindle for hours during these periods is poorly understood. Here we report that the bipolar spindle changes its molecular architecture during the long prometaphase/metaphase I in Drosophila melanogaster oocytes. By generating transgenic flies expressing GFP-tagged spindle proteins, we found that 14 of 25 spindle proteins change their distribution in the bipolar spindle. Among them, microtubule cross-linking kinesins, MKlp1/Pavarotti and kinesin-5/Klp61F, accumulate to the spindle equator in late metaphase. We found that the late equator accumulation of MKlp1/Pavarotti is regulated by a mechanism distinct from that in mitosis. While MKlp1/Pavarotti contributes to the control of spindle length, kinesin-5/Klp61F is crucial for maintaining a bipolar spindle during metaphase I arrest. Our study provides novel insight into how oocytes maintain a bipolar spindle during metaphase arrest.