Novel Mechanisms of Motility Induction in the Sperm of a Teleost Fish

本项目的重点是启动精子运动在太平洋鲱鱼（鲱）。我们的总体目标是定义一系列的细胞外和细胞内的事件，导致精子活力的启动，并确定两个分子，SMIF（精子活力启动因子）和HSAP（鲱鱼精子激活肽），诱导精子活力在这硬骨鱼的生物相关功能。 SMIF和HSAP是绒毛膜衍生的分子，它们启动不同的精子运动轨迹，并且通过不同的精子表面受体来启动，这些受体可能涉及独立的信号传导机制。 也有人认为，这两种运动启动系统在受精过程中具有不同的功能，即它们不仅仅是实现精子运动的冗余或备份手段。 这项研究是一项美国-日本的合作，这使得来自两个实验室的研究人员已经确定了不同的鲱鱼精子活力启动。 本研究的目的是确定这两种运动诱导分子的作用靶点、作用机制和生物学功能，本研究提出：1）免疫学和生物化学鉴定和表征SMIF和HSAP这两种运动诱导分子的精子表面受体。 2)通过特异性受体激活和抑制研究，确定受体在影响不同精子轨迹和诱导趋化性中的作用。 3)通过确定Ca 2+和Na+通量的相互依赖性、膜Na+-Ca 2+交换器的作用、蛋白激酶C磷酸化的参与以及通过描绘与不同精子运动模式和精子受体激活相关的离子通量，阐明与HSAP和SMIF运动启动相关的离子事件和信号机制。 4)通过使用抗体、信号转导和离子通道阻断剂以及选择性去除和添加每种分子，研究每种诱导剂在原位对精子活力诱导和受精的作用。

This project focuses on the initiation of sperm motility in the Pacific herring (Clupea pallasi). The overall goal is to define the series of extracellular and intracellular events that lead to the initiation of sperm motility and to determine the biologically relevant functions of the two molecules, SMIF (sperm motility initiation factor) and HSAP (herring sperm activating peptide), that induce sperm motility in this teleost fish. SMIF and HSAP are chorion-derived molecules that initiate different sperm motility trajectories, and do so via different sperm surface receptors that may involve independent signaling mechanisms. It has also been suggested that the two motility initiating systems have different functions in fertilization, that is, they are more than redundant or backup means of achieving sperm motility. The proposed research is a U.S.-Japan collaboration which brings researchers from two laboratories that have identified different herring sperm motility initiators. The proposal seeks to determine the targets, mechanisms of action and biological functions of both motility inducing molecules.The study proposes to: 1), Immunologically and biochemically identify and characterize the sperm surface receptors for the two motility initiators, SMIF and HSAP. 2) Determine the role(s) of the receptors in effecting different sperm trajectories and eliciting a chemotactic through specific receptor activation and inhibition studies. 3) Elucidate the ionic events and signaling mechanisms associated with HSAP and SMIF motility initiation by determining the interdependence of Ca2+ and Na+ fluxes, the role of a membrane Na+-Ca2+ exchanger, the involvement of phospohorylation by Protein Kinase C, and by delineating the ionic fluxes associated with the different sperm motility patterns and sperm receptor activation. 4) Investigate the role for each inducer in situ, with respect to sperm motility induction and fertilization, through the use of antibodies, signal transduction and ion channel blockers, and selective removal and addition of each molecule.