Abstract: 【Objective】The aim of this study was to analysis the effects of lncFAM200B in the lipid deposition in intramuscular preadipocytes of yak, which laid a foundation for further mechanism research. 【Method】The longissimus dorsi muscle tissue of yak was collected and used to separate intramuscular preadipocytes; The adenovirus mediated overexpression technology was used to realize the overexpression of lncFAM200B, and the siRNA interference and the siRNA interference technologies were used to analyze the function of lncFAM200B. The mRNA expression level of fat differentiation marker (PPARγ, C/EBPα and AP2) and the potential target (SIRT1 and PTEN ) genes of lncFAM200B were detected via real-time fluorescent quantitative PCR (RT-qPCR). Oil red O staining, triacylglycerol (TAG) determination and CCK-8 determination methods were used to detect intracellular lipid droplet deposition and preadipocyte proliferation.【Result】The results showed that overexpression of lncFAM200B not only significantly increased the fat differentiation genes (C/EBPα and AP2, P <0.05) expression level but also increased the lipid droplets deposition with large lipid droplets in the cells during induced differentiation. Conversely, lncFAM200B interference reduced the expression of PPARγ, C/EBPα and AP2 (P <0.05), and lipid droplet deposition. Furthermore, the triacylglycerol content was significantly higher than that of the control group (P <0.05) after lncFAM200B overexpression 4 days, but lower after siRNA interference 6 days. Moreover, the SIRT1 levels increased with time was first decreased and then increased trend, and the PTEN have the opposite trend during lncFAM200B overexpression, and the opposite results of the two genes obtained during lncFAM200B interference. In addition, the results of CCK-8 experiment showed that there was a significant difference in cell proliferation activity both in overexpression or interference group after 72 hours. 【Conclusion】Taken together, our results showed that lncFAM200B regulates yak adipose differentiation by influence the expression of fat differentiation marker (C/EBPα and AP2), and further affect the triacylglycerol content and the lipid droplet deposition, but the detail mechanism need to be further research efforts.

Key words: Yak, lncFAM200B, intramuscular preadipocytes, overexpression, interference