Cell polarity in sea urchin embryos: reorientation of cells occurs quickly in aggregates.
Cell polarity in sea urchin embryos: reorientation of cells occurs quickly in aggregates.
复制标题
海胆胚胎中的细胞极性：细胞的重新定向在聚集体中迅速发生。
DOI：
10.1016/0012-1606(88)90311-9
复制
发表时间：
1988
影响因子：
2.7
通讯作者：
McClay,DR
中科院分区：
文献类型：
--
作者：
Nelson,SH;McClay,DR
在以海胆胚胎早期囊胚阶段和卵裂阶段细胞聚集体细胞极性为中心的研究中，四种顶端成分被用作细胞顶端的标记。如果解离并在悬浮液中培养，则观察到细胞保持其极性数小时。聚集体中细胞的方向最初是随机的；然而，在 3 小时内，细胞重新定向，使其顶端-基底轴对应于聚集体中正确的内外位置。这种重新定向发生在聚集体中形成基底层或新的透明层之前，并且似乎是通过单个细胞的旋转或其他运动来发生的。每个细胞内的极性在重新定向期间保持不变。顶端表面抗原与丝状肌动蛋白浓度共定位。用细胞松弛素 B 处理分离的细胞会导致抗原失去其顶端位置，并最终分布在细胞外部。在未处理的细胞中，可见微管从与细胞核密切相关的两个焦点放射出来。用诺考达唑处理分离的细胞使顶端细胞表面标记及其相关肌动蛋白不受干扰，但导致细胞核失去其顶端位置。细胞松弛素 B 和秋水仙碱均可防止细胞聚集体重新定向。因此，极性对于细胞来说似乎是一个常数，并且它们在聚集体中的重新定向发生在胚胎外基质和基底层的极化释放之前。
Four apical components were used as markers for the apical end of the cell in studies centering on cell polarity in the early blastula stage of sea urchin embryos and in aggregates of cleavage stage cells. Cells were observed to maintain their polarity for several hours if dissociated and cultured in suspension. Orientation of cells in aggregates initially is random; however, within 3 hr the cells have reoriented so that their apical-basal axis corresponds to the correct inside-outside position in the aggregate. This reorientation occurs before formation of a basal lamina or a new hyalin layer in the aggregate, and appears to take place by a rotation or other movement of individual cells. The polarity within each cell is maintained during reorientation. An apical surface antigen is colocalized with concentrations of filamentous actin. Treatment of isolated cells with cytochalasin B causes the antigen to lose its apical position and eventually become distributed around the outside of the cell. Microtubules are visible radiating from two foci closely associated with the nucleus in untreated cells. Treatment of isolated cells with nocodazole leaves the apical cell surface marker and its associated actin undisturbed, but causes the nucleus to lose its apical position. Cytochalasin B and colchicine both prevent reorientation of cells in aggregates. Thus polarity appears to be a constant for the cells, and their reorientation in aggregates occurs prior to the polarized release of extraembryonic matrix and basal lamina.