过氧化物酶体增殖物激活受体γ(PPARG)具有多种剪接变体,在调节脂肪细胞分化和脂肪生成中起重要作用。然而,关于PPARG在水牛乳腺中的表达模式和对乳脂合成的影响知之甚少。在这项研究中,我们发现剪接变体中只有PPARG-X17和PPARG-X21在水牛乳腺中表达。氨基酸序列鉴定表明,PPARG-X17和PPARG-X21编码的蛋白质是核内非分泌型亲水性蛋白质。蛋白质结构域预测发现,只有PPARG-X21编码的蛋白质具有PPAR配体结合结构域(NR_LBD_PPAR),这可能导致两个接头之间的功能差异。进行RNA干扰(RNAi)和PPARG-X17和PPARG-X21在水牛乳腺上皮细胞(BMECs)中的过表达。结果表明,脂肪酸合成相关基因(ACACA,CD36,ACSL1,GPAT,AGPAT6,DGAT1)被RNAi和PPARG-X17和PPARG-X21的过表达显着修饰(p<0.05)。本研讨中检测到的各类FAs在RNAi后PPARG-X17或PPARG-X21显著下降(p<0.05)。过表达PPARG-X17或PPARG-X21显著降低SFA含量(p<0.05),而UFA显著增加(p<0.05),特别是在BMECs中的MUFA。总之,在BMEC中表达了两种PPARG剪接变体,它们可以通过改变多种脂肪酸合成相关基因的表达来调节FA的合成.本研究揭示了PPARG基因在水牛乳腺中的表达特点和功能,为进一步了解水牛乳中脂肪合成提供了参考。
Peroxisome proliferator-activated receptor γ (PPARG) has various splicing variants and plays essential roles in the regulation of adipocyte differentiation and lipogenesis. However, little is known about the expression pattern and effect of the PPARG on milk fat synthesis in the buffalo mammary gland. In this study, we found that only PPARG-X17 and PPARG-X21 of the splicing variant were expressed in the buffalo mammary gland. Amino acid sequence characterization showed that the proteins encoded by PPARG-X17 and PPARG-X21 are endonuclear non-secreted hydrophilic proteins. Protein domain prediction found that only the PPARG-X21-encoded protein had PPAR ligand-binding domains (NR_LBD_PPAR), which may lead to functional differences between the two splices. RNA interference (RNAi) and the overexpression of PPARG-X17 and PPARG-X21 in buffalo mammary epithelial cells (BMECs) were performed. Results showed that the expression of fatty acid synthesis-related genes (ACACA, CD36, ACSL1, GPAT, AGPAT6, DGAT1) was significantly modified (p < 0.05) by the RNAi and overexpression of PPARG-X17 and PPARG-X21. All kinds of FAs detected in this study were significantly decreased (p < 0.05) after RNAi of PPARG-X17 or PPARG-X21. Overexpression of PPARG-X17 or PPARG-X21 significantly decreased (p < 0.05) the SFA content, while significantly increased (p < 0.05) the UFA, especially the MUFA in the BMECs. In conclusion, there are two PPARG splicing variants expressed in the BMECs that can regulate FA synthesis by altering the expression of diverse fatty acid synthesis-related genes. This study revealed the expression characteristics and functions of the PPARG gene in buffalo mammary glands and provided a reference for further understanding of fat synthesis in buffalo milk.