Mammalian Gamete Surface Organization and Function

哺乳动物配子表面组织和功能

• 批准号: 6871332
• 负责人: Diana G Myles
• 金额: $ 33.19万
• 依托单位: UNIVERSITY OF CALIFORNIA AT DAVIS
• 依托单位国家: 美国
• 财政年份: 1996
• 资助国家: 美国
• 起止时间: 1996-05-01 至 2009-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6871332
• 关键词: acrosome; cell adhesion; cell adhesion molecules; cell cell interaction; egg /ovum; enzyme activity; enzyme substrate; fertilization; gene targeting; genetically modified animals; laboratory mouse; lipids; membrane fusion; membrane proteins; metalloendopeptidases; protein binding; protein localization; protein structure function; sperm; surface property; tissue /cell culture

DESCRIPTION (provided by applicant): Sperm-egg fusion occurs at a critical moment in fertilization at which the zygote is formed. In recent progress key proteins on the gamete surfaces have been implicated in membrane fusion. Current evidence indicates: (1) sperm ADAMs may have a role in fusion and (2) the egg tetraspanin CD9 and egg GPI-anchored proteins are required for fusion. ADAM proteins potentially have either cell-cell adhesion activity or protease activity and we propose that each of these is required for normal fertilization. Although gene knockout studies have shown that ADAMs 1, 2 and 3 are not required for fusion, it is possible that other ADAM family members have a role. We will test if a different ADAM acts in fusion of the sperm and egg plasma membranes. We will also test if a known protease, ADAM 24, acts to create the membrane block to polyspermy. Since gene deletion studies have shown that egg CD9 is required for fusion, we focus on CD9's mechanism of action and its localization to lipid microdomains. CD9 is known to have a soluble ligand and we will test if sperm have a related transmembrane ligand to which CD9 binds. In tissue culture lines, CD9 associates with many other proteins on the surface of a CD9-expressing cell. We will test if an egg CD9-associated protein binds to the sperm surface. Gene knockout studies have also shown that egg GPI-anchored proteins are required for fusion. We propose to identify the critical GPl-anchored protein(s) and analyze its mode of action. Since multiple proteins appear to play a role in fusion, we ask how their activities are coordinated. We propose that to function in fusion the active egg molecules must be organized into lipid microdomains. Thus, these studies are designed to combine molecular and cellular levels to bring new insight into the process of gamete membrane fusion.

描述（由申请人提供）：精子融合发生在施肥的关键时刻，形成了合子。在最近的进度中，配子表面上的关键蛋白与膜融合有关。当前的证据表明：（1）精子亚当可能在融合中起作用，（2）蛋白蛋白CD9和鸡蛋GPI锚定的蛋白需要融合。 亚当蛋白可能具有细胞 - 细胞粘附活性或蛋白酶活性，我们建议每一种都需要正常受精。尽管基因敲除研究表明，融合不需要亚当1、2和3，但其他亚当家族成员可能会发挥作用。我们将测试不同的亚当是否在精子和卵质膜的融合中起作用。我们还将测试已知的蛋白酶Adam 24是否作用着创建膜块到多菌的膜。由于基因缺失研究表明融合需要EGG CD9，因此我们着重于CD9的作用机理及其对脂质微区域的定位。已知CD9具有可溶性配体，我们将测试精子是否具有与CD9结合的相关跨膜配体。在组织培养品系中，CD9与表达CD9细胞表面的许多其他蛋白质相关联。我们将测试与CD9相关的蛋白与精子表面结合。基因敲除研究还表明，融合需要蛋GPI锚定的蛋白质。我们建议识别关键的GPL锚定蛋白质并分析其作用方式。由于多种蛋白质似乎在融合中起作用，因此我们询问它们的活动是如何协调的。我们建议要在融合中发挥作用，必须将活性卵分子组织到脂质微域中。因此，这些研究旨在结合分子和细胞水平，以使新的见解对配子膜融合的过程。