MAMMALIAN SPERM SURFACE MANNOSIDASE

哺乳动物精子表面甘露糖苷酶

• 批准号: 6090947
• 负责人: DAULAT R TULSIANI
• 金额: $ 23.19万
• 依托单位: VANDERBILT UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1995
• 资助国家: 美国
• 起止时间: 1995-09-29 至 2004-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6090947
• 关键词: cell cell interaction; cell membrane; egg /ovum; enzyme activity; enzyme biosynthesis; gene expression; hexosan; laboratory rat; mannosidase; protein localization; proteolysis; sperm; tissue /cell culture

This project focuses on the biochemical characterization of sperm surface mannosidase, a glycohydrolase believed to have a receptor-like role in sperm-egg interaction and on its complimentary glycan units on rat zona pellucida. The enzyme is an intrinsic plasma membrane (PM) protein with its catalytic domain oriented towards the outer surface of the intact spermatozoa. Since the enzyme is optimally active near neutral pH, it would be functionally active in physiological settings during in vitro and in vivo fertilization. The PI has demonstrated: a) the presence of the precursor and mature forms of alpha-D-mannosidase in PMs from the testis and on spermatozoa from the caput and corpus. Only the mature form is present in the cauda sperm PM; b) that the enzyme is synthesized and partially processed to the mature form in rat testicular germ cells; c) the role of protein-conjugated sugar residues in the induction of the acrosome reaction of spermatozoa; d) the cloning and characterization of rat ZP glycoconjugates; and e) the functional significance of the rat sperm surface mannosidase. The aims of this application are a continuation of ongoing studies. The first aim is designed to examine biosynthesis, proteolytic processing, intracellular trafficking, and cell surface expression of the sperm mannosidase in spermatogenic cells in culture. The second aim is to obtain evidence for the presence of complementary bioactive glycan units on rat ZP glycoproteins. The third aim is to examine the functional significance of the glycans in the sperm-egg interaction and in sperm activation. The proposed studies are part of the investigators' long-term goal to identify and chemically characterize the complementary molecules from the surface of opposite gametes which initiate sperm-egg interaction. This project will examine one of the receptor and ligand moieties believed to be involved in fertilization. Data from these studies will provide information on the role of the sperm surface mannosidase in egg adhesion and sperm activation during fertilization in the rat and will provide insight into mechanisms underlying the high degree of species-specificity observed during the fertilization process.

该项目重点研究精子的生化特征 表面甘露糖苷酶，一种糖水解酶，被认为具有类似受体的作用 精子-卵子相互作用及其在大鼠透明带上的互补聚糖单位 透明。该酶是一种内在质膜 (PM) 蛋白，其 催化结构域面向完整精子的外表面。 由于该酶在中性 pH 值附近具有最佳活性，因此它的功能 在体外和体内受精期间的生理环境中活跃。这 PI 已证明：a) 存在前体和成熟形式 睾丸 PM 和头顶精子中的 α-D-甘露糖苷酶 和语料库。尾部精子 PM 中仅存在成熟形式； b) 认为 酶在大鼠体内合成并部分加工成成熟形式 睾丸生殖细胞； c) 蛋白质结合糖残基的作用 诱导精子顶体反应； d) 克隆和 大鼠 ZP 糖复合物的表征； e) 功能意义 大鼠精子表面甘露糖苷酶。该应用程序的目的是 继续正在进行的研究。第一个目标旨在检查 生物合成、蛋白水解加工、细胞内运输和细胞 培养的生精细胞中精子甘露糖苷酶的表面表达。 第二个目的是获得互补性存在的证据 大鼠 ZP 糖蛋白上的生物活性聚糖单元。第三个目标是检查 聚糖在精卵相互作用中的功能意义 精子激活。拟议的研究是研究人员长期研究的一部分 目标是识别和化学表征互补分子 启动精子与卵子相互作用的相反配子的表面。这 该项目将检查被认为是受体和配体部分之一 参与受精。这些研究的数据将提供以下信息： 精子表面甘露糖苷酶在卵子粘附和精子激活中的作用 在大鼠受精期间，将提供对机制的深入了解 在此期间观察到的高度物种特异性的基础 受精过程。