SLO3 KO MOUSE: A TOOL TO REVEAL VOLTAGE-DEPENDENT PROCESSES IN SPERM FERTILITY

描述（由申请人提供）：精子获能是一系列在体内发生在女性生殖道中的分子过程，对精子使卵子受精的能力至关重要。获能的一个关键组成部分是精子质膜的超极化，但超极化的分子机制尚不清楚。我们先前通过使用SLO 3敲除（SLO 3-/-）小鼠表明，SLO 3钾通道是负责精子获能期间发生的超极化的主要离子通道，并且SLO 3-/-是男性不育的。我们还证明，来自SLO 3-/-小鼠的精子在精子活力和顶体反应（AR）方面存在重大缺陷。由于SLO 3通道是在获能过程中发生的膜电位（Em）变化的主要决定因素，现在应该可以揭示获能介质的组分如何触发SLO 3通道的激活以及SLO 3通道激活如何影响在获能和AR过程中活跃的其他信号传导途径。由于SLO 3-/-精子的运动性和AR受损，这两个事件都需要增加[Ca 2 +]i，我们将研究SLO 3通道激活和随后的Em变化如何影响获能和AR过程中发生的[Ca 2 +]i变化。本研究的总体目标是揭示精子膜电位（Em）变化在获能和AR中的作用。SLO 3-/-小鼠现在代表了一个宝贵的工具，使我们能够获得更大的实验控制精子Em，并将揭示Em的重要性，在每个元素的精子生理检查。SLO 3通道对受精至关重要的事实也表明，该基因内的遗传变异可能是男性个体生育力差异的原因。SLO 3通道也代表了设计和测试可用作避孕药物的这种重要通道特异性阻断剂的理想目标。最后，了解精子的电特性和外部离子环境的基本方面可能对提高临床IVF程序的效率具有重要意义。

DESCRIPTION (provided by applicant): Sperm capacitation is a poorly understood series of molecular processes that occur in vivo in the female genital tract, and is absolutely essential to a sperm's ability to fertilize an egg. A key component of capacitation is the hyperpolarization of the sperm plasma membrane, but the molecular mechanism underlying hyperpolarization was unknown. We previously showed by using a SLO3 knock-out (SLO3 -/-) mouse that the SLO3 potassium channel is the main ion channel responsible for the hyperpolarization that occurs during sperm capacitation and that the SLO3 -/- is male infertile. We also demonstrated that sperm from SLO3 -/- mice have major deficits in sperm motility as well as in the Acrosome Reaction (AR). Since SLO3 channels are the major determinant of changes in membrane potential (Em) that occur during capacitation, it should now be possible to reveal how the components of the capacitating media trigger the activation of SLO3 channels and how SLO3 channel activation affects other signaling pathways that are active during capacitation and the AR. Since SLO3 -/- sperm have impaired motility and AR, and both events require increases in [Ca2+]i, we will investigate how SLO3 channel activation and subsequent changes in Em affect the [Ca2+]i changes that occur during capacitation and the AR. The overall objective of this proposal is to reveal the role of sperm membrane potential (Em) changes in capacitation and the AR. The SLO3 -/- mouse now represents an invaluable tool which permits us to gain greater experimental control over sperm Em and will reveal the importance of Em in each element of sperm physiology examined. The fact that SLO3 channels are essential to fertilization also suggests the possibility that genetic variation within this gene accounts for differences in fertility among male individuals. SLO3 channels also represent an ideal target for designing and testing blockers specific for this essential channel that can be used as contraceptive drugs. Finally, knowledge of the electrical properties of sperm and the essential aspects of the external ionic environment may have important implications for improving the efficiency of clinical IVF procedures.