MAMMALIAN SPERM SURFACE ORGANIZATION AND FUNCTION

本提案的总体目标是了解 精卵质膜粘附融合过程。第一步 是顶体反应精子的尖端（内部 顶体膜（IAM）和卵质膜。 第二步 是这些精子表面赤道/后部头部之间的粘附 区域和卵质膜。 粘合后可能会有其他步骤 并导致膜融合。 以前的工作涉及两个精子表面 蛋白质，fertilin和cyritestin，作用于赤道/后部 头部区域结合步骤。 缺乏受精素的突变（基因敲除）小鼠， 制作。 同源突变的雄性不育。 目标1建议 利用这些小鼠来确定受精素在配子中的确切作用 膜结合、融合和卵活化。 cyritestin基因敲除 也正在生成。 目的2建议使用缺乏 Cyritestin为了确定Cyritestin在配子膜结合中的功能， 融合和卵激活。 目标3关注配子的第一步 膜相互作用，即精子IAM与卵子的接触 面 将测试该接触是否促进后续粘附 步骤和/或吞噬样过程，使IAM进入 卵细胞质 目的4提出研究精子后可能发生的步骤 结合，但在他们融合之前。 它将被测试，如果有一个 金属蛋白酶或必须在融合前起作用的表面ATP受体 发生。 目标5解决了鸡蛋上的什么分子的问题 质膜参与与精子的相互作用， 核聚变 它将确定卵子表面整合素，α-6-β-1， 用于fertilin或cyritestin的粘附伴侣。 它还将 向我们提出了一种独特的方法， 与小鼠精子融合，以识别另一种卵蛋白， 膜融合 了解配子融合的分子基础 这一过程可能会使辅助生殖技术有新的发展。 此外，所鉴定的功能性配子蛋白是潜在的 基于药理学和药理学的新型避孕方法的目标 免疫学方法。

The overall goal of this proposal is to understand each step in the process of sperm-egg plasma membrane adhesion and fusion. The first step is the contact between the tip of the acrosome-reacted sperm (the inner acrosomal membrane, IAM) and the egg plasma membrane. The second step is the adhesion between these sperm surface equatorial/posterior head region and the egg plasm membrane. Additional steps may follow adhesion and lead to membrane fusion. Previous work implicated two sperm surface proteins, fertilin and cyritestin, as acting in the equatorial/posterior head region binding step. Mutant (knockout) mice lacking fertilin were produced. The homologous, mutant males were infertile. Aim 1 proposes to use these mice to define the precise role of fertilin in gamete membrane binding, fusion and egg activation. A cyritestin gene knockout is also being generated. Aim 2 proposes to use male mice lacking cyritestin to determine cyritestin function in gamete membrane binding, fusion and egg activation. Aim 3 focuses on the first step in gamete membrane interaction, i.e. contact of the sperm IAM with the egg surface. It will be tested if this contact promotes later adhesion steps and/or the phagocytosis-like process that takes the IAM into the egg cytoplasm. Aim 4 proposes to study steps that may occur after sperm bind, but before they fuse. It will be tested if there is a metalloprotease or a surface ATP receptor that must act before fusion occurs. Aim 5 addresses the question of what molecules on the egg plasma membrane participate in interactions with the sperm that lead to fusion. It will determine if the egg surface integrin, alpha-6-beta-1, an adhesion partner for either fertilin or cyritestin. It will also propose to us a unique approach with a tissue culture cell line that fuses with mouse sperm to identify another egg protein that promotes membrane fusion. Understanding the molecular basis of the gamete fusion process may allow new developments in assisted reproduction. Furthermore, the identified, functional gamete proteins are potential targets for novel contraceptive methods based on pharmacological and immunological approaches.