脂肪细胞增殖分化和肌内脂肪沉积是影响肉牛生长发育与肉质的重要因素，也是培育优良肉牛品种的目标性状，但是脂肪作为机体重要的储能和内分泌器官，其平衡状态的维持必须经历细胞增殖维持与不同时期成脂分化的动态变化，涉及不同类型细胞间通讯互作、多分子信号传递及关键基因遗传修饰等复杂过程。尤其是参与细胞间信号转导的关键成脂调控因子和特异转运介质exosomes及其调控机制尚不明确。本项目拟以肉牛肌内不同分化程度的脂肪细胞为研究对象，建立preadipocyte成脂分化诱导技术体系，基于多组学联合分析技术筛查细胞增殖维持、分化特异调控因子和脂生物标志物，进而分离、特征化不同分化时期脂肪细胞源exosomes，并于细胞和活体组织水平解析exosomes对牛前体脂肪细胞增殖维持和脂肪细胞成脂分化及肌内沉脂的调控作用，为阐明肉牛肌内脂肪沉积的分子调控机制及发掘新的肉质性状功能基因提供新的技术依据和理论基础。

Adipocytes proliferation and differentiation and intramuscular fat deposition are important factors for development and meat quality in beef cattle. However, as an important energy storage and endocrine organ, it is necessary to undergo the dynamic changes of adipocyte proliferation and differentiation of adipocytes at different stages to maintain the balance of fat tissue. It also will involve complex processes such as different types of intercellular interactions, multi-molecular signaling transfer and genetic modification of key genes. In particular, the adipocytokines involved in intercellular signaling and specific transporter exosomes and their regulatory mechanisms are not yet clear. This project intends to establish a technical system for the induced differentiation of IMF preadipocytes during different development stages of beef cattle. Screening adipocyte proliferation, differentiation regulators and lipid biomarkers using multiple genomics techniques. And then, exosomes from adipocytes in different stages of differentiation were isolated, and the effects of exosomes on the proliferation of preadipocytes, adipocyte differentiation and intramuscular fat deposition were analyzed at the level of cells and tissues. This study aims to clarify functions and regulatory mechanisms of intramuscular fat deposition in beef cattle. These results will provide a solid theoretical foundation for excavating new candidate genes of beef cattle meat quality traits.