EXOCYTOTIC SIGNALING THROUGH SPERM RECEPTORS FOR EGGS

通过精子受体向卵子发出胞外信号

• 批准号: 6629128
• 负责人: DAVID Joel MILLER
• 金额: $ 13.76万
• 依托单位: UNIVERSITY OF ILLINOIS AT URBANA-CHAMPAIGN
• 依托单位国家: 美国
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-02-01 至 2005-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6629128
• 关键词: CD38 molecule; G protein; Xenopus oocyte; acrosome; benzoates; biological signal transduction; chimeric proteins; cytoplasm; egg /ovum; enzyme activity; enzyme inhibitors; exocytosis; fertility immunology; fertilization; galactosyltransferases; gene mutation; genetically modified animals; laboratory mouse; neutralizing antibody; protein tyrosine kinase

Our long-range objective is to develop a clearer fundamental understanding of the molecular basis of fertilization so that the process can be controlled to either promote fertilization or block it. Much progress has been made to identify ZP3, the protein in the mammalian egg coat that binds sperm and stimulates the acrosome reaction, the release of the acrosomal vesicle that must occur for sperm to penetrate the egg coat. Despite this progress, the identity of the ZP3 receptor on sperm has been elusive. One strong candidate is beta1,4-galactosyltransferase, an enzyme first discovered in the Golgi apparatus of somatic cells but later found on the surface of sperm. Beta1,4-Galactosyltransferase binds ZP3 but not other egg coat proteins. In addition to its role in gamete adhesion, beta1,4- galactosyltransferase acts to trigger the acrosome reaction in sperm. The acrosome reaction can be stimulated with antibodies to beta1,4-galactosyltransferase that act as mimics of ZP3 to bind and crosslink beta1,4-galactosyltransferase. There is evidence that binding beta1,4-galactosyltransferase stimulates at least some of the same signaling systems inside sperm that ZP3 stimulates, leading to the proposal that beta1,4- galactosyltransferase may be the major ZP3 receptor signaling the acrosome reaction. Mice with a targeted deletion of the beta1,4-galactosyltransferase gene, although fertile, produce sperm with severely compromised ability to acrosome react and penetrate the egg coat. In this proposal, the signaling systems that are activated by beta1,4-galactosyltransferase will be studied. The goals are to determine if binding beta1,4-galactosyltransferase specifically can completely reproduce all of the identified signaling systems activated by ZP3 binding, to study beta1,4-galactosyltransferase mutants to identify structural features necessary for signaling, and to identify proteins that interact with the portion of beta1,4- galactosyltransferase found in the cytosol. These studies will clarify the role of a sperm receptor for the egg coat in the acrosome reaction, a necessary step in the process of fertilization.

我们的远程目标是对受精的分子基础有更清晰的基本了解，以便可以控制该过程以促进受精或阻止施肥。 已经取得了很大的进步来识别ZP3，即哺乳动物卵外套中结合精子并刺激Adrosom反应的蛋白质，这是精子穿透鸡蛋涂层必须发生的粘体囊泡的释放。 尽管取得了这种进步，但精子上ZP3受体的身份仍然难以捉摸。 一个有力的候选者是Beta1,4-摩乳糖基转移酶，这是一种在体细胞的高尔基体设备中发现的酶，但后来在精子表面发现。 β1,4-半乳糖基转移酶结合ZP3，而没有其他卵外涂料蛋白。 除了其在配子粘附中的作用外，β1,4-半乳糖基转移酶还可以触发精子中的Astrosom反应。 可以用与β1,4-半乳糖基转移酶的抗体刺激的Adrosom反应，该抗体充当ZP3的模拟物，以结合和交叉链接β1,4-半乳糖基转移酶。 有证据表明，结合β1,4-半乳糖基转移酶至少刺激精子内部的某些相同的信号系统，即ZP3刺激刺激，导致建议β1,4-半乳糖基转移酶可能是主要的ZP3受体信号，使其信号传播。 具有靶向β1,4-半乳糖基转移酶基因的靶向缺失的小鼠虽然肥沃，但会产生具有严重损害的Adrosos反应能力并穿透卵外涂层的精子。 在此提案中，将研究由beta1,4-半乳糖基转移酶激活的信号系统。 The goals are to determine if binding beta1,4-galactosyltransferase specifically can completely reproduce all of the identified signaling systems activated by ZP3 binding, to study beta1,4-galactosyltransferase mutants to identify structural features necessary for signaling, and to identify proteins that interact with the portion of beta1,4- galactosyltransferase found in the cytosol. 这些研究将阐明精子受体对卵外涂层的作用，这是施肥过程中必要的步骤。