精原干细胞对精子细胞发育和动物物种的繁衍起着重要的作用。作为成体干细胞，精原干细胞的自我更新与分化的调控机制尚不清楚。在对不同发育期小鼠精原干细胞基因表达的对比分析中，我们发现多个在精原干细胞中高表达的基因，其中akt1s1的表达比体细胞高约12倍。AKT1S1是AKT和mTORC1信号通路的中介，近期研究发现两者在精原干细胞的自我更新与维持中起重要作用，其分子机制有待深入研究。本项目通过详细分析akt1s1在小鼠精原干细胞中的表达及其蛋白相互作用，揭示akt1s1的作用机制；利用精原干细胞体外培养系统中对akt1s1的敲减和变异，分析akt1s1对精原干细胞自我更新与维持的影响；结合对akt1s1在精原干细胞中的条件敲除小鼠的分析，阐明akt1s1生物学功能的分子机制。通过这些研究，我们希望对精原干细胞自我更新与分化的调控机理作深入的理解，为寻找有效治疗相关生殖疾病的方法奠定基础。

Spermatogonial stem cells (SSCs) play important functions for the development of male gamete and the propagation of animal species. Mammalian spermatozoa are developed from SSCs through the process of spermatogenesis that is composed of mitosis, meiosis and spermiogenesis. In addition, SSCs have been an ideal model system for the study of adult stem cells. However, the molecular mechanisms of SSC self-renewal and differentiation remain largely unclear. Our previous studies using cell sorting methods isolated developing SSCs at various stages in mice and compared their differential gene expression profiles. Numerous genes were found to highly enrich in SSCs, including akt1s1, of which the expression is about 12 times higher than that of somatic cells. Recent studies also showed that growth factor GDNF emitted from sertoli cells can elicit its function through SSC receptor Gfra1/cRet and Akt signaling pathway; in addition, SSC marker gene plzf regulates SSC self-renewal and growth by negatively regulating mTORC1 activity and Gfra1 expression in SSCs. Thus to uncover the function of akt1s1 is important for the understanding of SSC regulation. Through the analyses of akt1s1 expression and its protein interactions in SSCs, the molecular mechanisms of its functions will be dissected. Using gene modifications, such as shRNA and mutagenesis methods, the functional roles of akt1s1 will be studied in cultured SSC colonies. Further more, by applying mouse genetics, the physiological function and molecular mechanisms of akt1s1 will be analyzed in conditional knockout mouse model. The proposed research will not only help to decipher the molecular circuitry of SSC self-renewal and differentiation, but will also help to find novel means to treat relevant reproductive diseases.