甜菜碱是高效的甲基供体，对肝脏脂肪代谢有重要的调控作用。我们前期研究发现，饲喂甜菜碱可有效缓解皮质酮诱导的产蛋鸡脂肪肝，且与肝脏脂肪酸合成关键调节因子固醇调节元件结合蛋白1（SREBP-1）蛋白表达下调密切相关，但其蛋白表达被抑制的分子机制尚不清楚。我们提出假说，即甜菜碱可能提高SREBP-1 mRNA上3'UTR区域的N6-腺苷酸甲基化（m6A）修饰水平，降低其mRNA稳定性，从而抑制SREBP-1蛋白表达。因此，本项目拟采用Western blot、miCLIP-seq、m6A位点突变、过表达及siRNA等技术，研究甜菜碱对产蛋鸡肝脏中以及正常和m6A位点突变或修饰被抑制时原代培养鸡胚肝细胞中SREBP-1 mRNA的m6A修饰水平和稳定性及其蛋白表达水平的影响，以揭示甜菜碱抑制产蛋鸡肝脏SREBP-1蛋白表达的分子机制，为合理应用甜菜碱防治产蛋鸡脂肪肝提供科学试验依据。

Betaine, as a highly active methyl donor, plays an important role in regulating hepatic fat metabolism. Our previous studies have demonstrated that betaine supplementation could alleviate corticosterone induced chicken fatty liver, which was closely associated with the downregulation of protein expression of the key regulator-sterol regulatory element binding protein 1 (SREBP-1) in hepatic fatty acid synthesis. However, the underlying molecular mechanisms of the inhibited SREBP-1 protein expression remain unclear. We hypothesized that betaine would down-regulate SREBP-1 protein expression possibly via increasing the N6-methyladenosine (m6A) modification on 3'UTR of SREBP-1 mRNA and decreasing the transcript stability. In the present project, therefore, Western blot, miCLIP-seq, m6A mutation, overexpression, siRNA techniques, and so on, will be used to investigate the effects of betaine treatment on SREBP-1 mRNA m6A levels, its stability and protein expressions in the liver of laying hens or in both normal primary cultured hepatocytes of chicken embryos and those hepatocytes in the case of m6A site’s mutation or m6A modification’s inhibition, so as to elucidate the molecular mechanisms of betaine for inhibiting SREBP-1 protein expression in the liver of laying hens. The outcomes from the present project will provide scientific bases for the prevention and treatment of fatty liver in laying hens.