CHANGES IN TOPOGRAPHY OF SEA-URCHIN EGG AFTER FERTILIZATION
CHANGES IN TOPOGRAPHY OF SEA-URCHIN EGG AFTER FERTILIZATION
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DOI：
10.1083/jcb.71.1.35
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发表时间：
1976-01-01
影响因子：
7.8
通讯作者：
SHAPIRO, BM
中科院分区：
文献类型：
--
作者：
EDDY, EM;SHAPIRO, BM
通过扫描和透射电子显微镜研究了受精后海胆卵的地形变化。用二硫苏糖醇处理紫球海胆卵，以改变卵黄层并防止受精膜的形成。二硫苏糖醇处理导致微绒毛的形状、长度和直径变得更加不规则。胰蛋白酶处理的微绒毛进行了类似的修改。这种效果似乎不是由于破坏质膜下的细胞骨架元素，无论是秋水仙素还是细胞松弛素B改变微绒毛形态。卵黄层可能起维持未受精卵表面形态的作用。由于二硫苏糖醇处理的鸡蛋没有提高受精膜，扫描电子显微镜可以用来直接观察受精后卵质膜的修改。波的皮质颗粒胞吐作用开始在附着点的精子的特点是出现坑，随后打开，释放皮质颗粒内容物，并留下凹陷的卵表面。在胞吐过程中插入的颗粒周膜被视为原始卵表面残留的微绒毛斑块之间的光滑斑块。这产生了一个马赛克表面，其膜的数量是未受精卵的两倍多。镶嵌表面随后重组，以适应插入的膜材料的微绒毛的伸长。重组前出现的水泡和膜涡表明存在一个不稳定的质膜重组的中间状态。胞吐和镶嵌膜的形成不被秋水仙素或细胞松弛素B阻断，但细胞松弛素B处理可阻断微绒毛的伸长。
Changes in the topography of the sea urchin egg after fertilization were studied by scanning and transmission electron microscopy. Strongylocentrotus purpuratus eggs were treated with dithiothreitol to modify the vitelline layer and to prevent formation of a fertilization membrane. Dithiothreitol treatment caused the microvilli to become more irregular in shape, length and diameter, than those of untreated eggs. The microvilli were similarly modified by trypsin treatment. This effect did not appear to be due to disruption of cytoskeletal elements beneath the plasma membrane, for neither colchicine nor cytochalasin B altered microvillar morphology. The vitelline layer may act in the maintenance of surface form of unfertilized eggs. Since dithiothreitol-treated eggs did not elevate a fertilization membrane, scanning electron microscopy could be used to directly observe modifications in the egg plasma membrane after fertilization. The wave of cortical granule exocytosis initiated at the point of attachment of the fertilizing sperm was characterized by the appearance of pits that subsequently opened, releasing the cortical granule contents and leaving depressions upon the egg surface. The perigranular membranes inserted during exocytosis were seen as smooth patches between the microvillous patches remaining from the original egg surface. This produced a mosaic surface with more than double the amount of membrane of unfertilized eggs. The mosaic surface subsequently reorganized to accommodate the inserted membrane material by elongation of microvilli. Blebs and membranous whorls present before reorganization suggested the existence of an unstable intermediate state of plasma membrane reorganization. Exocytosis and mosaic membrane formation were not blocked by colchicine or cytochalasin B, but microvillar elongation was blocked by cytochalasin B treatment.