MicroRNAs are a class of highly conserved and widely distributed non-coding RNAs. It is known that miR-26b has a high abundance in adipose tissue and is considered to be an effective regulator of adipogenesis. However, it is unclear whether miR-26b-5p, the product of miR-26b precursor, has the same effect as miR-26b. In the present study, we explored the potential role of miR-26b-5p in preadipocyte differentiation of goats. We found that the expression of miR-26b-5p had dramatic change during goat intramuscular preadipocyte differentiation. Transfection and RT-qPCR revealed that overexpression of miR-26b-5p increased the level of adipogenic marker genes and lipid accumulation in goat preadipocyte, suggesting that miR-26b-5p positively regulates goat preadipocyte differentiation. Furthermore, bioinformatics analysis and dual fluorescein reporter assays were performed to predict and validate the targets of miR-26b-5p. The results showed that miR-26b-5p has a binding site in the 3′UTR of FGF21 and overexpression of miR-26b-5p significantly down-regulated the expression of FGF21 mRNA. Luciferase activity assays confirmed that miR-26b-5p is a positive regulator of goat intramuscular preadipocyte via targeting FGF21. These findings provide reference for further revealing of the regulatory networks of goat fat metabolism and contribute to a better understanding of intramuscular fat deposition in goats.

MicroRNA 是一类高度保守、分布广泛的非编码 RNA。已知miR-26b在脂肪组织中具有高丰度，被认为是脂肪生成的有效调节剂。然而，尚不清楚miR-26b前体的产物miR-26b-5p是否与miR-26b具有相同的作用。在本研究中，我们探讨了 miR-26b-5p 在山羊前脂肪细胞分化中的潜在作用。我们发现在山羊肌内前脂肪细胞分化过程中，miR-26b-5p的表达发生了显着变化。转染和 RT-qPCR 显示 miR-26b-5p 的过表达增加了山羊前脂肪细胞中脂肪生成标记基因的水平和脂质积累，表明 miR-26b-5p 正调节山羊前脂肪细胞的分化。此外，进行生物信息学分析和双荧光素报告基因检测以预测和验证 miR-26b-5p 的靶标。结果表明 miR-26b-5p 在其 3'UTR 有一个结合位点。FGF 21 和 miR-26b-5p 的过表达显着下调FGF 21 mRNA 的表达。荧光素酶活性测定证实，miR-26b-5p 是通过靶向FGF 21对山羊肌内前脂肪细胞的正调节。这些发现为进一步揭示山羊脂肪代谢的调节网络提供参考，有助于更好地了解山羊的肌内脂肪沉积.