MECHANISMS OF MAMMALIAN FERTILIZATION

卵囊（ZP）是一种厚厚的细胞外膜，包裹着所有哺乳动物的卵。的 小鼠卵ZP由三种糖蛋白组成，称为mZP 1 -3。编码糖蛋白的基因是 在2-3周的时间内仅由生长的小鼠卵母细胞表达， 糖蛋白组装成构成ZP的交联丝。之一 糖蛋白，mZP 3，被识别的一种种物种特异性的方式，自由游泳，顶体完整 精子与未受精的卵子结合。与mZP 3结合诱导精子经历顶体 反应，一种细胞胞吐作用。只有顶体反应的精子才能穿透ZP并融合 与卵细胞质膜结合形成受精卵在本申请中，描述了实验， 继续解决有关ZP糖蛋白和鸡蛋ZP的重要问题，具体目标 该建议的目的是评估mZP 2和mZP 3多肽一级结构之间的关系 以及使用生长的小鼠卵母细胞将这些糖蛋白分泌和组装成细丝， 转基因小鼠和转染的哺乳动物细胞。提出ZP的分泌和组装 在一些实施方案中，糖蛋白由mZP 2和mZP 3多肽的特异性结构域调节。许多 提出的实验是可能的，因为获得的结果和方法开发期间， 上一个补助期。这些实验包括使用突变和野生型mZP基因， 将多种表位标记的mZP cDNA构建体显微注射到生长的小鼠卵母细胞中， 携带突变转基因的转基因小鼠和转染的哺乳动物细胞。结果进行 实验应该提供重要的分子信息， ZP糖蛋白的一级结构，从生长的卵母细胞分泌ZP糖蛋白， 将ZP糖蛋白组装成长丝。鉴于老鼠和老鼠之间的巨大相似性 和人类ZP糖蛋白以及小鼠和人类受精之间，很可能 这里获得的信息也适用于人类。此外，这项研究可能 预防ZP的新型可逆避孕方法的发展的重要结果 在人类卵子发生过程中形成。

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.