DEVELOPMENT OF CORTICAL POLARITY IN MOUSE EGGS - INVOLVEMENT OF THE MEIOTIC APPARATUS
DEVELOPMENT OF CORTICAL POLARITY IN MOUSE EGGS - INVOLVEMENT OF THE MEIOTIC APPARATUS
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DOI：
10.1016/0012-1606(85)90320-3
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发表时间：
1985-01-01
影响因子：
2.7
通讯作者：
CHEN, DY
中科院分区：
文献类型：
--
作者：
LONGO, FJ;CHEN, DY
进行实验以确定小鼠卵中皮质极性的起源及其与减数分裂装置的可能关系。覆盖减数分裂器（无微绒毛区域）的成熟卵皮质的特征是不存在微绒毛和增厚的肌动蛋白层。相比之下，未成熟卵母细胞的表面完全被密集的微绒毛覆盖，并被均匀的肌动蛋白层所覆盖。当诱导成熟时，减数分裂纺锤体在未成熟卵母细胞的中心形成，然后向周边移动。与减数分裂纺锤体的皮质定位相一致的是无微绒毛区域的形成，即微绒毛的损失和与卵皮质的该区域相关的肌动蛋白层的增厚。如果未成熟的卵母细胞在细胞松弛素 B 中孵育，减数分裂纺锤体就会形成；然而，它们未能向周边移动，并且没有形成无微绒毛的区域。在秋水仙碱中孵育的卵母细胞没有形成减数分裂纺锤体，尽管染色体浓缩并定位于无微绒毛区域发育的皮质。细胞松弛素 B 处理的成熟卵保持完整的减数分裂纺锤体，并表现出无微绒毛区域的消失和皮质肌动蛋白的减少。尽管减数分裂纺锤体消失，但用秋水仙碱处理的成熟卵的染色体仍与无微绒毛区域相关。有时，经秋水仙碱处理的鸡蛋拥有> 1条位于皮质的染色体，每条染色体都与无微绒毛的区域相关。涉及减数分裂纺锤体向卵母细胞皮质的运动以及皮质极性的发育和维持的机制显然对细胞松弛素 B 敏感。与减数分裂染色体定位到卵皮质相称的是皮质肌动蛋白的重组和无微绒毛区域的形成。
Experiments were carried out to determine the origin of cortical polarity in mouse eggs and its possible relation to the meiotic apparatus. Cortices of mature eggs overlying the meiotic apparatus (microvillus-free area) were distinguished by an absence of microvilli and a thickened layer of actin. In contrast, the surfaces of immature oocytes were covered entirely with a dense population of microvilli and were subtended by a uniform layer of actin. When induced to undergo maturation, meiotic spindles formed in the center of immature oocytes and then moved peripherally. Coincident with the cortical localization of the meiotic spindle was the formation of a microvillus-free area, i.e., a loss of microvilli and a thickening of the actin layer associated with this region of the egg cortex. If immature oocytes were incubated in cytochalasin B, meiotic spindles formed; however, they failed to move peripherally and microvillus-free areas did not develop. Oocytes incubated in colchicine did not form meiotic spindles, although the chromosomes condensed and became localized to cortices where microvillus-free areas developed. Cytochalasin B-treated mature eggs maintained intact meiotic spindles and exhibited a disappearance of microvillus-free areas and a reduction in cortical actin. The chromosomes of mature eggs treated with colchicine remained associated with microvillus-free areas despite the disappearance of meiotic spindles. Occasionally, colchicine-treated eggs possessed > 1 cortically located mass of chromosomes, each of which was associated with a microvillus-free area. Mechanisms involving the movement of the meiotic spindle to the oocyte cortex and development and maintenance of cortical polarity apparently are cytochalasin B sensitive. Commensurate with the localization of meiotic chromosomes to the egg cortex is the reorganization of cortical actin and the formation of a microvillus-free area.