Understanding the molecular basis for sperm function: the sperm connecting piece and sperm motility

精子是一种运动细胞，它将父亲的遗传信息传递给卵母细胞。为了发挥作用，精子形态必须正常，精子必须获得活力。通常，动物（和人类）男性不育与精子形态和功能异常有关。一种表型，通常观察到的无功能精子，是精子头部脱离所造成的“脆弱”精子连接件。对于养牛业来说，高公牛繁殖力是重要的，并且具有经济后果。 我们发现并鉴定了一种在动物中保守的精子蛋白p12，它由鸟氨酸脱羧酶抗酶3基因Oaz3编码。p12调节蛋白磷酸酶活性，这是精子运动的重要调节因子。在精子尾部，p12可能调节精子尾部的运动性，但它也存在于连接段。一个小鼠模型表明，缺乏p12导致一个脆弱的连接片表型和异常的尾部运动。这种表型与养牛业中的观察结果非常相似。 我们建议调查如何p12参与调节精子尾部运动和连接件。 我们将a）分析p12与连接片段中的哪些蛋白质结合，B）分析p12是否调节连接片段蛋白质的磷酸化，c）p12与Mypt3的关联对精子尾部磷酸酶活性和运动性调节的重要性，以及d）使用p12的新型转基因小鼠模型（使用特异性p12突变蛋白）分析p12在精子尾部运动性中的功能。 我们的实验将解决养牛业的一个常见问题，并将提供工具，使养牛业能够使用生殖技术来诊断精子和优化程序。

Spermatozoa are motile cells that transfer the father's genetic information to the oocyte. To function, sperm morphology must be normal, and sperm must acquire motility. Often, animal (and human) male infertility is related to abnormal sperm morphology and function. One phenotype, commonly observed for non-functional sperm, is sperm head detachment caused by a "fragile" sperm connecting piece. For cattle industry, high bull fertility is important and of economic consequence. We have discovered and characterized a sperm protein, p12 conserved among animal species, encoded by ornithine decarboxylase antizyme 3, Oaz3 gene. p12 modulates protein phosphatase activity, an important regulator of sperm motility. In sperm tails p12 likely regulates sperm tail motility but it is also present in the connecting piece. A mouse model shows that lack of p12 causes a fragile connecting piece phenotype and abnormal tail motility. This phenotype closely resembles observations made in the bovine industry. We propose to investigate how p12 is involved in regulation of sperm tail motility and in the connecting piece. We will a) analyze to which proteins p12 binds in the connecting piece, b) analyze if p12 regulates phosphorylation of connecting piece proteins, c) the importance of the association of p12 with Mypt3 on phosphatase activity in the sperm tail and regulation of motility, and d) analyze p12 function in sperm tail motility using novel transgenic mouse models for p12 using specific p12 mutant proteins. Our experiments will address a common problem in the cattle industry, and will provide tools to equip industry using reproductive technologies to diagnose sperm and optimize procedures.