Genomic and Physiological Mechanisms of Androgen Signaling: Steroid 5-Reductase Knockout Investigation in Frogs

随着越来越多的环境污染物对动物(包括人类)起内分泌干扰作用，迫切需要评估雄性激素(雄激素)是如何调节和产生的，以了解雄激素生物合成改变对健康的影响。利用测试内分泌干扰物最好的水生模型之一--西方爪蛙，我培育出了独特的青蛙突变系，以模拟雄激素干扰。青蛙的变态能力代表了一种独特的动物模型，它以外部发育的大胚胎为特征，研究发育生理的方方面面(与任何哺乳动物模型相比)。这些突变的青蛙不具有被称为类固醇5-还原酶的功能性酶，这种酶能够产生最强大的雄激素之一。通过研究一系列的形态和生理终点，以及最先进的基因敲除和测序技术，以及转录和表观遗传学分析，这一研究计划将推动青蛙雄激素信号传递领域的发展。我将验证这一假设，即类固醇5-还原酶在青蛙繁殖中有几个角色，但除了生殖外，还有生理功能。我的主要研究目标是研究类固醇5-还原酶如何调控发育和生殖。更具体地说，我将使用我独特的青蛙突变系来研究类固醇5-还原酶在青蛙发育过程中的作用。此外，利用这些突变的青蛙，我将研究它们的生殖功能，我发现的一种新的雄激素在青蛙中的作用，以及甲状腺激素对这些突变的影响。最后，我将评估另一类突变体的繁殖缺陷，即缺乏甲状腺激素受体的青蛙。这项拟议的研究将直接有助于国际社会努力了解雄激素信号的基本方面。在更实际的范围内，这项研究可能应用于针对环境污染，这些污染将通过激活或停用水生和半陆地物种的雄激素产生来发挥作用。在青蛙上的基本发现对于理解所有脊椎动物的生殖功能具有很高的相关性。总之，从国际合作到本地实验室团队合作，我的培训理念将为我的HQP提供他们需要的所有资源，以获得卓越的专业培训，并在分子内分泌学和比较内分泌学方面追求成功的研究生涯。

With the increased presence of environmental contaminants acting as endocrine disruptors to animals, including in humans, there is a critical need to assess how male hormones (androgens) are regulated and produced in order to understand the health consequences of the alteration of androgen biosynthesis. Using one of the best aquatic models for endocrine disruptor testing, the Western clawed frog, I have produced unique lines of frog mutants to mimic androgen disruption. With their metamorphosing ability, frogs represent a unique animal model featuring large externally developing embryos to study all aspects of developmental physiology (as compared to any mammalian models). These mutant frogs do not possess the functional enzymes, called steroid 5-reductases, capable of producing one of the most powerful androgens. Investigating a series of morphological and physiological endpoints paired with state-of-the-art gene knock-out and sequencing technologies, as well as transcriptomics and epigenetics analysis, this research program will move the field of frog androgen signaling forward. I will be testing the hypothesis that steroid 5-reductases have several roles in frog reproduction, but also physiological functions aside from reproduction. My overarching research objective is to characterize how steroid 5-reductases regulate development and reproduction. More specifically, I will investigate the roles of steroid 5-reductases during frog development using my unique lines of frog mutants. In addition, using these mutant frogs, I will study their reproductive function, the roles of a novel androgen I have discovered to be active in frogs, and the effects of the thyroid hormones on these mutants. Lastly, I will assess the reproductive deficiencies of another category of mutants, i.e., frogs lacking the thyroid hormone receptors. The proposed research will contribute directly to international efforts to understand the fundamental aspects of androgen signaling. On a more practical scale, this research may have applications for targeting environmental contamination that would act through the activation or deactivation of androgen production in aquatic and semi-terrestrial species. Fundamental discoveries in frogs have high relevance for understanding reproductive function in all vertebrates. Altogether, from international collaborations to local lab teamwork, my training philosophy will offer my HQP all the resources they need to acquire exceptional professional training to pursuing a successful research career in molecular endocrinology and comparative endocrinology.