Pod1是转录因子bHLH家族的一员，在哺乳类性别决定、性别分化和性腺发育中有重要的作用。然而，至今为止，在非哺乳类脊椎动物中，有关Pod1基因在性别分化和性腺发育中的功能我们知之甚少。申请人前期研究基础表明，Pod1基因在鱼类性别分化和性腺发育中有重要的作用。因此，本项目拟进一步利用模式生物青鳉，采用基因转移、morpholino介导的基因敲降和过表达等技术，配合整体原位杂交、免疫荧光定位等方法，深入研究Pod1基因在鱼类胚胎发育和性别分化中的功能；利用酵母双杂交、Pull-down和免疫共沉淀等技术筛选并鉴定与Pod1相互作用的蛋白，揭示Pod1基因表达调控的分子机制。本研究结果将首次阐明Pod1基因在鱼类胚胎发育和性别分化中的功能及其作用的分子机理，加深人们对鱼类性别决定和性别分化的分子机制的了解，而且对哺乳类特别是人类性别决定和性别分化机制的研究也有一定的借鉴作用。

Pod1 is one member of the basic helix-loop-helix (bHLH) family of transcription factors implicated in the regulation of sexual differentiation and gonadal development in mammals. However, to date, little is known about the possible role of Pod1 in nonmammalian vertebrate sexual differentiation and gonadl development. We cloned and characterized Pod1 gene from tilapia. Our primary data indicate for the first time that Pod1 is not only necessary for the onset of sexual differentiation, but also plays an important role in gonadal development in the teleost. In this study, we will use two different ways, Pod1 gene knock-down and overexpression, to deternimine the possible function of Pod1 during medaka embryonic development and sexual differentiation by employing whole mount in situ hybridization (WISH) and immunohistochemistry. Furthermore, we will performe three methods, yeast two-hybrid system, pull-down and co-immunoprecipitation (Co-IP), to screen and identify the interaction proteins of Pod1 and explore the molecular mechanism of transcriptional regulation of Pod1. In summary, our study will determine for the first time the possible function of Pod1 and the molecular mechanism of function during embryonic development and sexual differentiation in medaka and will extend the comprehension of the molecular mechanism of fish sex determination and sexual differentiation. Moreover, our study will help to resolve the molecular mechanism of the mammalian especially for human sex determination and sexual differentiation.