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SURFACE REORGANIZATION OF THE ACTIVATED VERTEBRATE EGG

活化脊椎动物卵的表面重组

基本信息

批准号：
3314464
负责人：
NATHAN H HART
金额：
$ 6.43万
依托单位：
RUTGERS, THE STATE UNIV OF N.J.
依托单位国家：
美国
项目类别：
财政年份：
1984
资助国家：
美国
起止时间：
1984-01-01 至 1988-02-29
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/3314464
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

项目摘要

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.

受精通常会触发与膜结合的戏剧性胞吐皮质颗粒从外周卵子胞浆进入细胞外太空。由马赛克组成的蛋面由皮质颗粒和原始卵质膜的膜。这个这些镶嵌表面成分的结构、作用和命运尚未得到已经完全确定了。传统的概念一直是大脑皮质颗粒膜组件永久整合到鸡蛋中质膜；卵子容纳引入的多余的膜其表面由微绒毛延伸而成。然而，涂层的鉴定激活卵细胞质中的小泡及近期的初步研究研究表明颗粒过程中细胞外表面标记的摄取胞吐现象表明，马赛克表面的重组似乎包括通过形成内吞作用使膜内化水泡。使用常规的透射电子显微镜和扫描电子显微镜，冷冻骨折复制，透射电子显微镜细胞化学和定量放射性标记分析，以及大的，淡水鱼的半透明卵作为分析的模型系统，这研究将：1)提供进一步的形态和实验证据从激活(受精)的鸡蛋表面回收膜；2) 重建内吞作用序列并测定细胞内卵皮质中处理内吞细胞膜的途径(S)； 3)确定内吞作用的机制是否与卵子皮质细胞质中的亚质膜丝状系统。这个这项研究的结果将提供更全面的了解脊椎动物的卵子激活过程，包括人类(其中已知会发生皮质颗粒反应)，以及对可能的早期卵面在控制后期发育事件中的作用。对整个行业发生的重组变化的了解卵子表面的激活对生育控制有明显的影响并将建立一个重要的框架，以供未来的研究在卵子发育的早期计划中进行。