丙酮酸脱氢酶β亚基（PDHB）催化丙酮酸成为乙酰辅酶A（acetyl-CoA），是将糖酵解和三羧酸循环代谢途径连接起来的关键酶。目前研究表明，PDHB基因的表达水平与肌内脂肪（IMF）含量成正相关，然而该基因在肌内脂肪形成过程中的功能尚不清楚。本研究拟采用腺病毒介导的过表达和RNAi技术，对PDHB基因在牛肌内前体脂肪细胞分化和脂滴形成过程中的作用进行研究，明确该基因在牛肌内前体脂肪细胞分化过程中是否发挥作用；同时对该基因的启动子进行克隆及活性分析，找到关键的转录因子结合位点，采用定点突变实验结合凝胶组织迁移率（EMSA）和染色体免疫共沉淀（ChIP）技术对关键转录因子进行验证。这些研究结果将有助于揭示PDHB基因在牛肌内脂肪形成过程中的作用机理和进一步了解肌内脂肪形成过程的调控机制，从而为提高肉牛肌内脂肪含量提供理论基础。

The enzyme encoded by PDHB catalyzes pyruvate into acetyl-CoA, which is a linkage of glycolysis and tricarboxylic acid cycle (TCA) pathway. Previous studies showed the expression level of PDHB was positively correlated with intramuscular fat (IMF). However, the mechanism that the cattle PDHB gene plays a role in the development of IMF is not clear. In this study, adenovirus mediated over-expression and RNAi technology will be used to analyze the role of PDHB gene in the intramuscular preadipocyte differentiation and the formation of lipid droplet to explore whether the PDHB gene plays a role in the intramuscular preadipocyte differentiation. On the other hand, we will clone and analyze the promoter of the cattle PDHB gene, and find the key transcription factor binding sites. Then, these key transcription factors will be confirmed by the site-directed mutation experiment combined with electrophoretic mobility shift assay (EMSA) and chromatin immunoprecipitation (ChIP). These results will help to reveal the role of PDHB gene in the development of IMF and further understand the regulation mechanism in the development of IMF，and provide an important basis for improving IMF in cattle.