Rspondin(Rspo1)信号通路在哺乳动物雌性性别决定和分化过程中有重要作用。然而该信号通路在鱼类性别决定和分化过程中作用的研究尚未见报道。我们首次提出Rspo1信号通路在硬骨鱼类雌性性别决定和分化过程中有重要作用。本项目将以罗非鱼和青鳉为研究对象，利用实时定量PCR、原位杂交和免疫组化等方法研究Rspo1信号通路基因的时空表达模式。通过激素处理研究Rspo1信号通路和雌激素合成的关系。并通过基因突变（XX）和过表达（XY）等实验从失活和获得基因功能两个方面研究Rspo1信号通路在硬骨鱼类雌性性别决定中的功能。通过荧光素酶报告基因分析研究Rspo1信号通路调控雌激素合成的关键转录因子和生殖细胞减数分裂相关因子的分子机制。最终阐明硬骨鱼类Rspo1信号通路通过与雌激素合成协同作用，并通过调节生殖细胞减数分裂启动，进而在硬骨鱼类雌性性别决定和分化过程中发挥重要作用。

Rspondin-１ (RSPO1) signalng pathway plays an important role in female sex determination and differentiation in mammalian species. However, studies on the roles of Rspo1 signaling pathways in sex determination and differentiation in fish have not been reported. For the first time, we proposed that Rspo1 signaling pathway acts as a key factor in controling the direction of gonadal differentiation in female teleosts. By using tilapia and medaka as models, we will use real-time PCR, in situ hybridization and immunohistochemistry etc. to study the spatial and temporal expression profiles of Rspo1 and two types of β-catenin. Hormone treatment experiments will be performed to investigate the relationship between Rspo1 signaling pathways and estrogen pathway.In vivo gene mutation by medaka ENU library screesning (loss of function in XX) and over-expression (gain of function in XY) experiments will be carried out to figure out the functions of Rspo1 signaling pathway in female sex determination and differentiation. Promoter analysis using dual luciferase system will be performed to clarify the molecular mechanism that the Rspo1/β-catenin signal pathway regulates the key factors, which are related to meiosis and the synthesis of estrogen. The final aim of this study is to elucidate that Rspo1/β-catenin signaling pathway plays essential role in female sex determination and differentiation in the teleosts by coordinating with estrogen and regulating　the meiotic initiation of germ cell.