Mammalian Fertilization: Identifying the second sperm factor that induces residual calcium oscillations and its contributions to egg activation

在精子分子和诱导Ca 2+的机制方面，我们的知识一直存在空白 哺乳动物卵子的振荡Ca 2+释放触发卵子激活和胚胎发育启动 包括人类在内的所有哺乳动物一种精子分子，精子因子，SF，后来被鉴定为 磷脂酶zeta，PLCz，被认为是唯一负责诱导Ca 2+释放的SF， PLCz失活突变导致人类男性不育。然而，Plcz基因敲除小鼠生育力低下， 并引起残余的Ca 2+振荡，表明备份机制的功能。组件 以及后备系统的生理作用是我们知识中的空白。这些差距代表着严重的 障碍，因为直到我们克服它们，我们不了解卵激活的Ca 2+调节 事件或可以客观地诊断，预防或治疗与卵子激活失败相关的不孕症。的 长期目标是了解Ca 2+振荡的分子基础， 计划在施肥。目的是确定触发这些Ca 2+振荡的精子分子 在鸡蛋里。老鼠和它的配子是完美的模型，因为它们易于操作 和基因改造。支持这一提议的核心假设是，一个或多个精子 除了PLCz外，PLC还有助于传递Ca 2+信号，并可作为备用机制 以防Plcz功能障碍。这一假设是根据大量的初步数据提出的。的 所提出的研究的基本原理是一旦所有诱导振荡的精子分子都已知， 评估了它们的调节作用，以及它们在生殖管理中的诊断价值和应用， 物种充分探索我们计划通过追求以下具体目标来检验我们的中心假设：1） 鉴定PLC 1 z-KO精子中在受精时诱导Ca 2+振荡的分子; 2）确定PLC 1 z-KO精子中在受精时诱导Ca 2+振荡的分子。 备份系统对典型受精的Ca 2+响应和卵激活事件的贡献。 在目标1下，我们将使用Trim-21 mRNA、特异性抗体、CRISPR产生的KO小鼠系， 免疫荧光，Ca 2+监测和胚胎培养，以确定PLCd 4是否是 备份系统。在目标2下，我们将采用类似的方法，但针对不同的分子， 机制，以确定Ca 2+备份系统的典型的Ca 2+信号的贡献 受精这项应用的研究是创新的，因为它代表了对 其他精子PLC的作用，包括一个删除导致男性不育，在振荡的 受精拟议项目的贡献是重大的，因为我们的目标是完善 治疗卵子激活失败，改善胚胎发育，发现男性生育能力的指标， 确定新的避孕目标。最后，我们期望在理解分子方面取得进展， 以及诱导哺乳动物胚胎发育的调节机制。

There is a persistent gap in our knowledge of the sperm molecules and mechanisms that induce Ca2+ oscillations in mammalian eggs. Ca2+ release triggers egg activation and initiation of embryo development in all mammals, including human beings. A sperm molecule, the sperm factor, SF, later identified as Phospholipase zeta, PLCz, was thought to be the only SF responsible for inducing Ca2+ release, and PLCz inactivating mutations cause infertility in human males. However, Plcz knockout mice are subfertile and evoke residual Ca2+ oscillations, suggesting the function of a backup mechanism. The component(s) and the physiological role of the backup system are gaps in our knowledge. These gaps represent serious impediments, as until we overcome them, we do not understand the Ca2+ regulation of egg activation events or can objectively diagnose, prevent or treat infertility associated with egg activation failure. The long-term goal is to understand the molecular basis of the Ca2+ oscillations that unfold the developmental program at fertilization. The objective is to identify the sperm molecules that trigger these Ca2+ oscillations in the egg. The mouse and its gametes are perfect models because they are amenable to manipulation and genetic modifications. The central hypothesis underpinning this proposal is that one or more sperm PLCs besides PLCz contribute to delivering the Ca2+ signal and could serve as the backup mechanism in case of Plcz disfunction. This hypothesis was conceived based on extensive preliminary data. The rationale for the proposed research is that once all sperm molecules that induce oscillations are known, their regulation assessed, and their diagnostic value and application to the reproductive management of species fully explored. We plan to test our central hypothesis by pursuing the following specific aims: 1) Identify the molecule(s) in PLC1z-KO sperm that induce Ca2+ oscillations at fertilization; 2) Determine the contribution of the backup system to the Ca2+ responses and egg activation events of typical fertilization. Under Aim 1, we will use Trim-21 mRNA, specific antibodies, CRISPR-generated KO mouse lines, immunofluorescence, Ca2+ monitoring, and embryo culture to determine if PLCd4 is the active factor of the backup system. Under Aim 2, we will employ similar methods but target different molecules and mechanisms to ascertain the contribution of the Ca2+ backup system to the Ca2+ signal of typical fertilization. The research in this application is innovative because it represents a fresh examination of the role of other sperm PLCs, including one whose deletion causes male infertility, in the oscillations of fertilization. The contributions of the proposed project are significant because we aim to perfect the treatment of egg activation failure, improve embryo development, discover indicators of male fertility, and identify novel targets of contraception. Finally, we anticipate progress in understanding the molecules and regulatory mechanisms that induce embryo development in mammals.