circYAP1调控奶山羊乳腺脂肪酸合成的分子机制研究

The composition of fatty acid is the key factor to the flavor and quality of goat milk. Thus, studying the regulation mechanism of fatty acid synthesis is of great significance for improving the taste and quality of goat milk. Previous research showed that the expression of circYAP1 was significant lower in the period of peak-lactation than early-lactation, indicating that circYAP1 plays an important role in lactation. YAP1 is closely related to the composition of fatty acid in goat milk. Moreover, miR-141 promotes milk fat metabolism by targeting YAP1, and a miR-141 binding site in circYAP1 sequence was found. Therefore, we hypothesized that circYAP1 regulates fatty acid synthesis by competitively binding to miR-141. However, the effect and regulation mechanism of circYAP1 are still unclear. The objective of this study is to construct the signal transduction network map of circYAP1 regulation of fatty acid synthesis by the experimental techniques of qRT-PCR, Western blot, RNA FISH, ChIRP, RNA pull down and RIP. The effect and regulation mechanism of circYAP1 on fatty acid synthesis in mammary glands of dairy goats will be revealed and new research ideas and theoretical basis for improving the taste and quality of goat milk will be provided.

脂肪酸组成是影响羊奶风味和品质的关键因素，研究羊奶中脂肪酸合成的调控机制对于改善羊奶口感、提高羊奶品质具有重要意义。申请人发现circYAP1在泌乳盛期表达水平显著低于泌乳前期，暗示circYAP1对泌乳有重要作用。初步研究表明YAP1与羊奶中脂肪酸的成分密切相关，miR-141能够靶向YAP1促进乳脂代谢，而circYAP1序列中又存在着miR-141的结合位点，故推断circYAP1竞争性结合miR-141调控脂肪酸合成，但作用及调控机制仍不明确。因此，本项目以circYAP1为研究对象，以qRT-PCR、Western blot、RNA FISH、ChIRP、RNA pull down和RIP等为技术手段，以构建circYAP1调控脂肪酸合成信号转导网络图谱为研究目标，旨在解析circYAP1对奶山羊乳腺脂肪酸合成的作用及调控机制，为改善羊奶口感和品质提供新的研究思路和理论依据。

研究羊奶中脂肪酸合成的调控机制对于提高羊奶品质、改善羊奶风味具有重要的意义。本项目利用高通量测序技术在不同泌乳阶段奶山羊乳腺组织中筛选出circ003429和circ007071作为研究对象。我们发现circ003429和circ007071能够分别靶向结合miR-199a-3p和miR-103-5p，过表达circ003429和circ007071分别下调了奶山羊乳腺上皮细胞中miR-199a-3p和miR-103-5p的表达量。过表达miR-199a-3p提高了细胞中甘油三酯的含量，同时降低了靶基因YAP1的表达量，而过表达circ003429降低了细胞中甘油三酯的含量，并提高了YAP1的表达量和饱和脂肪酸的含量。此外，过表达miR-103-5p降低了细胞中甘油三酯的含量和靶基因PPARγ的表达量。过表达circ007071提高了细胞中甘油三酯的含量和饱和脂肪酸的含量，并提高了PPARγ的表达量。综上所述，circ003429和circ007071能够分别靶向miR-199a-3p和miR-103-5p，解除靶基因YAP1和PPARγ的抑制作用，从而调控脂肪酸和甘油三酯的合成。