MECHANISMS OF MAMMALIAN FERTILIZATION

超出所提供的空间。卵带（ZP）是一层厚厚的细胞外膜，包裹着所有哺乳动物的卵子。鼠卵ZP由三种糖蛋白组成，称为mZP1-3。编码糖蛋白的基因在生长的小鼠卵母细胞中只在2-3周内表达，新生的糖蛋白被组装成交联的细丝，构成ZP。其中一种糖蛋白，mZP3，以一种特定的方式被自由游动的，顶体完整的精子与未受精卵结合时识别。与mZP3结合诱导精子进行顶体反应，这是细胞胞外分泌的一种形式。只有顶体反应的精子才能穿透ZP并与卵质膜融合形成受精卵。在本申请中，实验描述了继续解决关于ZP糖蛋白和卵细胞ZP的重要问题，本提案的具体目的是评估mZP2和mZP3多肽初级结构与这些糖蛋白分泌和组装成细丝之间的关系，使用生长中的小鼠卵母细胞，转基因小鼠和转染的哺乳动物细胞。ZP糖蛋白的分泌和组装受rnZP2和mZl>3多肽的特定结构域的调控。由于在以前的拨款期间所获得的结果和发展的方法，许多拟议的实验成为可能。实验包括使用突变型和野生型mZP基因，将多种表位标记的mZP cDNA构建物微注射到生长中的小鼠卵母细胞中，携带突变转基因的转基因小鼠，以及转染的哺乳动物细胞。这些实验结果应该为ZP糖蛋白初级结构、生长中的卵母细胞分泌ZP糖蛋白以及ZP糖蛋白组装成长丝之间的可能关系提供重要的分子信息。鉴于小鼠和人类ZP糖蛋白之间以及小鼠和人类受精之间的巨大相似性，这里获得的信息很可能也适用于人类。此外，该研究可能对开发新的可逆避孕方法产生重要影响，这些方法可以防止人类卵子发生过程中ZP的形成。网站性能 ======================================== 节结束 ===========================================

EXCEED THE SPACE PROVIDED. The zona peltucida (ZP) is a thick extracellular c0at that surrounds all mammalian eggs. The mouse egg ZP consists of three glycoproteins, called mZP1-3. Genes encoding the glycoproteins are expressed exclusively by growing mouse oocytes during a 2-3 week period and the nascent glycoproteins are assembled into crosslinked filaments that constitute the ZP. One of the glycoproteins, mZP3, is recognized in a species-specific manner by free-swimming, acrosome-intact sperm when they bind to unfertilized eggs. Binding to mZP3 induces sperm to undergo the acrosome reaction, a form of cellular exocytosis. Only acrosome-reacted sperm can penetrate the ZP and fuse with egg plasma membrane to form a zygote. In this application, experiments are described that continue to address significant questions about ZP glycoproteins and the egg ZP, The Specific Aim of this proposal is to evaluate relationships between mZP2 and mZP3 polypeptide primary structures and secretion and assembly of these glycoproteins into filaments using growing mouse oocytes, transgenic mice, and transfected mammalian cells. It is proposed that secretion and assembly of ZP glycoproteins is regulated by specific domains of rnZP2 and mZl>3 polypeptides. Many of the experiments proposed are possible because of results obtained and methodolgy developed during the previous grant period. The experiments include the use of mutated and wild-type mZP genes, a variety of epitope-tagged mZP cDNA constructs microinjected into growing mouse oocytes, transgenic mice carrying mutated transgenes, and transfected mammalian cells. Results of these experiments should provide important molecular information about possible relationships between ZP glycoprotein primary structures, secretion of ZP glycoproteins from growing oocytes, and assembly of ZP glycoproteins into long filaments. In view of the great similarities between mouse and human ZP glycoproteins and between fertilization in mice and humans, it is very likely that information obtained here will apply to humans as well. Furthermore, the research could have important consequences for development of novel reversible contraceptive methods that prevent ZP formation during oogenesis in humans. PERFORMANCE SITE ========================================Section End===========================================