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

随着环境污染物对动物（包括人类）的内分泌干扰物的增加，迫切需要评估如何调节和产生雄性激素（雄激素），以便了解雄激素生物合成改变对健康的影响。我用一种最好的水生动物模型来测试内分泌干扰物，西方爪蛙，我培育出了独特的青蛙变种来模拟雄激素干扰。由于它们的变形能力，青蛙代表了一种独特的动物模型，具有巨大的外部发育胚胎，可以研究发育生理学的各个方面（与任何哺乳动物模型相比）。这些变异的青蛙不具备一种叫做类固醇5-还原酶的功能酶，这种酶能够产生一种最强大的雄激素。研究一系列形态和生理终点，结合最先进的基因敲除和测序技术，以及转录组学和表观遗传学分析，该研究计划将推动青蛙雄激素信号传导领域的发展。我将测试一个假设，即类固醇5-还原酶在青蛙的繁殖过程中有多种作用，但除了繁殖之外，还具有生理功能。我的主要研究目标是描述类固醇5-还原酶如何调节发育和繁殖。更具体地说，我将研究类固醇5-还原酶在青蛙发育过程中的作用，使用我独特的青蛙突变体。此外，利用这些突变青蛙，我将研究它们的生殖功能，我发现在青蛙中活跃的一种新型雄激素的作用，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生殖缺陷，即缺乏甲状腺激素受体的青蛙。拟议的研究将直接有助于了解雄激素信号传导的基本方面的国际努力。在更实际的规模上，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灭活水生和半陆生物种的雄激素产生而起作用。青蛙的基本发现对于理解所有脊椎动物的生殖功能具有高度相关性。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提供他们获得卓越专业培训所需的所有资源，以追求分子内分泌学和比较内分泌学的成功研究事业。

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.