Tudor-SN是一个多功能的保守蛋白质，参与细胞代谢、增殖、应激等过程，但其信号转导通路尚未揭示。本课题组前期发现Tudor-SN正向调节奶牛乳腺上皮细胞（DCMEC）的乳蛋白和乳脂肪合成及细胞增殖，本研究拟阐明其调节乳蛋白和乳脂肪合成的信号转导通路，以深入揭示其调节泌乳的分子机理。通过激素、氨基酸等外源信号刺激及利用RNA干扰等技术，阐明已知DCMEC主要泌乳信号转导途径对Tudor-SN基因表达和入核的调控作用；利用Co-IP结合质谱分析鉴定Tudor-SN的胞浆和胞核相互作用蛋白质组以及Tudor-SN磷酸化位点，从中筛选鉴定催化Tudor-SN磷酸化的蛋白激酶1-2个，进一步揭示Tudor-SN上游信号途径通过激酶促进Tudor-SN磷酸化入核的信号通路；从中筛选鉴定Tudor-SN下游转录因子1-2个，并揭示Tudor-SN同其相互作用调节乳蛋白和乳脂肪合成的转录调控机理。

Tudor staphylococcal nuclease (Tudor-SN) is an evolutionarily conserved and multi-functional protein implicated in a variety of cellular processes, recent research reveal that it participates in protein and fat synthesis, cell proliferation, cell cycle, stress response, etc. But untill now, the mechanism of the Tudor-SN signaling pathway is less known. Our previous study revealed that Tudor-SN was associated with milk protein and fat synthesis and cell proliferation. Using gene functinal study approaches, we further found that Tudor-SN positively regulated milk protein synthesis in dairy cow mammary epithelial cell (DCMEC). In the present research, we want to unveil the signal transduction pathway of Tudor-SN leading to milk protein and fat synthesis in DCMEC, to deeply elucidate the molecular mechanism of Tudor-SN in the regulation of milk synthesis. First, we want to elucidate the regulation of the known main signaling transduction pathways on the expression and nuclear localization of Tudor-SN, using environmental stimuli, such as hormones and amino acids, in conjunction with gene knock down approach. The co-immunoprecipitation (Co-IP) and MALDI-TOF/TOF peptide mass fingerprinting will be used to identify the protein interactomes of Tudor-SN in the cytoplasm and nucleus. We further want to identify 1-2 of the kinases from the cytoplasmic interactome of Tudor-SN, furthermore, we will unveil the mediation of these kinases through which the upstream signaling tranduction pathway of Tudor-SN triggers Tudor-SN phosphorylation and nuclear localization. Next, we further want to identify 1-2 of the transcription factors from the nuclear interactome of Tudor-SN, furthermore, we will unveil the mechanism that Tudor-SN interacts with these transcription factors to regulate the transcriptional activation of milk protein and fat synthesis.