Cytokeratin dynamics during oocyte maturation in the hamster requires reaching of metaphase I.
Cytokeratin dynamics during oocyte maturation in the hamster requires reaching of metaphase I.
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DOI：
10.1046/j.1432-0436.1996.6020087.x
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发表时间：
1996-05
期刊：
影响因子：
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通讯作者：
C. Plancha
中科院分区：
文献类型：
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作者：
C. Plancha
微丝和微管等细胞骨架成分在哺乳动物卵母细胞成熟、受精和早期胚胎发育过程中起着重要作用。然而，其他组件，如细胞质中间丝，在这些关键事件的作用仍然在很大程度上是未知的。卵母细胞成熟是卵子发生的最后一步，在排卵之前。在成熟过程中，细胞骨架发生了一些细胞学变化，包括减数分裂纺锤体的形成、细胞器的重新分布、膜极化和第一极体的排出。在这项研究中，我们确定组织和细胞角蛋白在仓鼠卵母细胞成熟的重排。培养完全生长的卵母细胞，然后使用显微镜免疫标记技术观察，以监测成熟过程中特定减数分裂阶段的细胞角蛋白动力学。在前体蛋白酶-I-逮捕完全生长的仓鼠卵母细胞，细胞角蛋白局限于4-10个大的皮质聚集体，对应于广泛的中间丝网状结构。这些大的聚集体从中期I开始分散成多个小斑点，直到中期II成熟期结束，其中细胞角蛋白表现出均匀分布的斑点图案。然而，减数分裂中期II的进展是不必要的细胞角蛋白重新分配发生，因为早熟逮捕中期I卵母细胞也表现出分散的细胞质病灶在培养期结束。细胞角蛋白的再分布对诺考达唑和细胞松弛素D不敏感，表明其独立于微管和微丝发生。相反，卵丘细胞和蛋白质合成都需要细胞角蛋白修饰发生在卵母细胞成熟。这些结果表明，细胞角蛋白中间丝存在于完全生长的仓鼠卵母细胞中，并且在成熟过程中发生了由中期I阶段的实现触发的细胞角蛋白的显著重组。
Cytoskeletal components like microfilaments and microtubules are known to play important roles during the processes of oocyte maturation, fertilization and early embryonic development in mammals. However, the roles of other components such as cytoplasmic intermediate filaments, during these critical events remain largely unknown. Oocyte maturation is the final step of oogenesis, immediately before ovulation. Several cytological changes involving the cytoskeleton take place during the maturation process, including meiotic spindle formation, redistribution of cell organelles, membrane polarization and first polar body emission. In this study we determined the organization and rearrangements of cytokeratins during hamster oocyte maturation. Fully grown oocytes were cultured and then visualised using microscopic immunolabelling techniques to monitor the cytokeratin dynamics at specific meiotic stages of the maturation process. In prophase-I-arrested fully grown hamster oocytes, cytokeratins are confined to 4-10 large cortical aggregates, corresponding to extensive meshworks of intermediate filaments. These large aggregates disperse into multiple small spots starting at metaphase I until the end of the maturation period at metaphase II, where cytokeratin exhibits a homogeneously distributed spotted pattern. However, meiotic progression to metaphase II is not necessary for cytokeratin redistribution to occur, since precociously arrested metaphase I oocytes also exhibit dispersed cytoplasmic foci at the end of the culture period. The redistribution of cytokeratins is insensitive to nocodazole and cytochalasin D suggesting it occurs independent of microtubules and microfilaments. In contrast, both cumulus cells and protein synthesis are required for cytokeratin modifications to take place during oocyte maturation. These results show that cytokeratin intermediate filaments are present in the fully grown hamster oocyte, and that a striking reorganization of cytokeratins, triggered by attainment of the metaphase I stage, occurs during maturation.