SURFACE REORGANIZATION OF THE ACTIVATED VERTEBRATE EGG

活化脊椎动物卵的表面重组

• 批准号: 3314463
• 负责人: NATHAN H HART
• 金额: $ 5.5万
• 依托单位: RUTGERS, THE STATE UNIV OF N.J.
• 依托单位国家: 美国
• 财政年份: 1984
• 资助国家: 美国
• 起止时间: 1984-01-01 至 1986-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3314463
• 关键词: cell membrane; cytochalasins; egg /ovum; electron microscopy; exocytosis; ferritin; fertilization; freeze etching; fresh water environment; immunofluorescence technique; immunoperoxidase; membrane activity; pinocytosis; scanning electron microscopy

Fertilization typically triggers the dramatic exocytosis of membrane-bound cortical granules from the peripheral egg cytoplasm into the extracellular space. An egg surface of mosaic composition is constructed, derived from membranes of the cortical granules and the original egg plasmalemma. The structure, role and fate of these mosaic surface components has not been fully ascertained. The traditional concept has been that the cortical granule membrane components become permanently integrated into the egg plasma membrane; the egg accomodates the excess membrane introduced into its surface by microvillar elongation. However, identification of coated vesicles in the cytoplasm of the activated egg and recent preliminary studies showing uptake of extracellular surface labels during granule exocytosis suggest that reorganization of the mosaic surface appears to include internalization of membrane through formation of endocytotic vesicles. Using routine TEM and SEM, freeze fracture replication, TEM cytochemistry, and quantitative radiolabel assay, and the large, translucent egg of a freshwater fish as a model system for analysis, this study will: 1) provide further morphological and experimental evidence for the recovery of membrane from the activated (fertilized) egg surface; 2) reconstruct the sequence of endocytosis and determine the intracellular pathway(s) in the egg cortex by which endocytosed membrane is handled; and 3) determine if the mechanism underlying the endocytosis is associated with a subplasmalemmal filamentous system in the egg cortical cytoplasm. The results of this study will provide a more comprehensive understanding of the egg activation process in vertebrates, including humans (where a cortical granule response is known to occur), and insight into the possible role of the early egg surface in the control of later development events. A knowledge of the reorganizational changes that take place over the entire egg surface upon activation has distinct implications for fertility control and will establish an important framework upon which future studies can be conducted on the early program of egg development.

受精通常会触发膜结合蛋白的胞吐作用， 皮层颗粒从外周卵细胞质进入细胞外 空间 一个镶嵌组成的鸡蛋表面被构建，来自于 皮层颗粒膜和原始卵质膜。 的 这些镶嵌表面成分的结构、作用和命运还没有被 完全确定。 传统观念认为大脑皮层 颗粒膜成分永久地整合到卵中 质膜;卵容纳引入的过量膜。 其表面微绒毛伸长。 然而，涂层的识别 激活卵细胞质中的小泡， 研究显示在颗粒形成过程中细胞外表面标记的摄取 胞吐作用表明镶嵌表面的重组似乎 包括通过形成胞吞作用 囊泡 利用常规TEM和SEM、冷冻断裂复制、TEM 细胞化学和定量放射性标记分析，以及大的， 半透明的淡水鱼卵作为模型系统进行分析， 研究将：1）提供进一步的形态学和实验证据， 从活化（受精）卵表面恢复膜; 2） 重建胞吞序列，确定胞内 卵皮质中处理内吞膜的途径;以及 3)确定内吞作用的潜在机制是否与 在卵皮层细胞质中的亚质膜丝状系统。 的 这项研究的结果将提供更全面的了解， 包括人类在内的脊椎动物的卵激活过程（其中 皮质颗粒反应是已知的发生），并洞察到可能的 早期卵表面在控制后期发育事件中的作用。 了解整个组织发生的重组变化， 卵表面激活后对生育控制有明显的影响 并将建立一个重要的框架，在此基础上，未来的研究可以 进行卵子发育的早期计划。