由于对奶牛乳蛋白合成调控的分子机制缺乏了解，生产中对奶牛乳蛋白产量、乳蛋白组成的营养调控受到严重限制。已知氨基酸是乳蛋白合成的前体物并且可作为信号分子参与乳蛋白合成调控，但其详细调控机制不清。G蛋白偶联受体T1R1/T1R3已被证明在多种组织中参与氨基酸的直接感知，并且本课题组的前期结果初步显示乳腺组织中存在功能性的T1R1/T1R3。因此，本研究拟从体内和离体两个层面，以奶牛乳腺外植体和奶牛乳腺上皮细胞系作为模型，利用基因超表达和RNA干扰技术，结合蛋白质活性特异性阻断技术，分析乳腺T1R1/T1R3的氨基酸感知能力，探讨T1R1/T1R3对奶牛乳腺必需氨基酸转运的调控及其分子机制，揭示T1R1/T1R3通过mTORC1信号通路调控乳蛋白合成的机制，从而搞清乳腺T1R1/T1R3的功能及其作用机制。研究结果可为奶牛乳蛋白产量、乳蛋白组成的营养调控及奶牛品种的分子设计提供新的理论依据。

Due to the lack of regulation mechanism on dairy cattle milk biosynthesis, it is difficult to regulate milk protein production and milk protein quality accurately. Amino acids can not only function as precursor of milk protein, but also as signal molecules to regulate milk production. Its regulation mechanism remains unclearly. T1R1/T1R3, a G-protein-coupled receptor, has been reported to function as a sensor of amino acids in several tissues. Moreover, we detected functional T1R1/T1R3 in dairy cattle mammary gland recently. Herein, in the present study, we are going to use mammary gland explants and mammary epithelial cells as models, employ gene over-expression, RNAi and antagonistic protein techniques, to investigate response of T1R1/T1R3 to amino acids in mammary gland, study the function of T1R1/T1R3 on amino acid transport and its regulation mechanism, explore the functional mechanisms of T1R1/T1R3 on milk protein biosynthesis through mTORC1 pathway, so that to discover the functional mechanisms of T1R1/T1R3 in dairy cattle mammary gland.