MECHANISMS OF MAMMALIAN FERTILIZATION/POLYSPERMY BLOCK

小鼠卵子受精引发一系列信号事件 那 包括细胞内钙离子的一过性升高，刺激 皮质颗粒胞吐导致改变 分区 透明带，招募母体mRNAs，并完成 减数分裂 细胞周期和向有丝分裂细胞周期的转化。这些事件 构成一个称为“卵子激活”的过程。以…为类比 分化的体细胞，精子可能会启动这些事件 一个鸡蛋 激活使用G蛋白偶联的信号转导通路。 这个 精子-卵子质膜相互作用的初始事件 最终 导致细胞内信号转导可能涉及黏附和膜 融合 由精子配体和卵子受体介导的过程。一个目标 的 这项建议将审查潜在的下游的作用 效应器 对于钙离子的作用，钙调素依赖的蛋白激酶II， 专一 EGG激活事件。这将通过使用 构成要素 该激酶的活性形式，以及一系列特定的 抑制剂 这种酶的活性。另一个目标将直接涉及G的角色 蛋白质类 在精子诱导卵子激活中使用反义方法 烧蚀 特异性鸡蛋G蛋白亚基的功能及其评价 这 对卵子激活事件的影响。最后一个目标将使用精子- 一种称为受精素的特定蛋白质，被认为是一种 专一 精卵质膜中的配体/黏附分子 通过化学交联实验来识别相互作用 蛋 受精素结合蛋白。由于受精素含有一种 去整合素 一个鸡蛋整合素可以作为结合蛋白的结构域 受精素。 鸡蛋整合素在调节这个过程中的作用将是 考查 使用转基因反义方法，其中特定的卵子 整合素是 靶向和对精子结合和卵子激活的影响是 评估过了。这些研究的结果主要集中在分子基础上。 精子-卵子相互作用和卵子激活并将翻译 直接发送到 辅助生殖技术的临床环境。 此外， 这些研究解决了细胞生物学中的基本问题， 也就是说，细胞 相关异种细胞间黏附诱导的信号转导 至 调节胞吐作用、细胞周期和翻译的问题 控制力。

Fertilization of mouse eggs initiates a cascade of signaling events that include a transient rise in intracellular Ca2+, the stimulation of cortical granule exocytosis that results in modifications of the zona pellucida, recruitment of maternal mRNAs, and completion of the meiotic cell cycle and conversion to a mitotic cell cycle. These events constitute a process termed "egg activation". By analogy to differentiated somatic cells, the sperm may initiate these events of egg activation using G protein-coupled signal transduction pathways. the initial events of sperm-egg plasma membrane interaction that ultimately lead to intracellular signaling may involve adhesion and membrane fusion processes mediated by a sperm ligand and an egg receptor. One aim of this proposal will examine the role of the potential downstream effector for Ca2+ action, the calmodulin-dependent protein kinase II, on specific events of egg activation. This will be done by using a constitutively active form of this kinase, as well as a battery of specific inhibitors of this enzyme. Another aim will address directly the role of G proteins in sperm-induced egg activation by using an antisense approach to ablate the function of specific egg G protein subunits and then assessing this effect on events of egg activation. The last aim will use a sperm- specific protein called fertilin that has been implicated as a specific ligand/adhesion molecule involved in sperm-egg plasma membrane interactions to identify by chemical crosslinking experiments the egg binding protein for fertilin. Since fertilin contains a disintegrin domain an egg integrin may serve as the binding protein for fertilin. The role of an egg integrin in mediating this process will be examined using a transgenic antisense approach in which specific egg integrins are targeted and the effects on sperm binding and egg activation are assessed. Results of these studies focus on the molecular basis of sperm-egg interaction and egg activation and will translate directly to the clinical setting of assisted reproductive technologies. Moreover, these studies address fundamental questions in cell biology, namely, cell adhesion-induced signaling between heterologous cells that relate to questions of regulated exocytosis, cell cycle, and translational control.