Fat deposition is an important economic trait in farm animals. However, it is difficult to genetically improve intramuscular fat deposition via trait-based cattle breeding. The main objectives of this study were to analyze the factors about beef flavor, and to detect functional microRNA (miRNA, miR) associated with intramuscular fat deposition in Yanbian cattle. Longissimus dorsi samples from six steers were separated into high- and low-fat groups (n = 3 each) based on the marbling score, and transcriptomic analysis was performed using miRNA sequencing. A total of 33 miRNAs and 38 genes were found to be differentially expressed in the high- and low-fat groups. Quantitative real-time polymerase chain reaction was performed to validate the sequencing results. Integrated miRNA–mRNA analysis revealed that miRNA-associated target genes were primarily associated with skeletal muscle development. However, some of the miRNAs (miR-424 etc.) and genes (ATF3 etc.) were also associated with fat metabolism. A targeted relationship between miR-22-3p and the WFIKKN2 gene and its involvement in adipocyte differentiation were confirmed experimentally. The study findings may provide potential candidate molecular targets for the selection of cattle with improved meat quality.

中文翻译：

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microRNA-mRNA 综合分析揭示了 microRNA 在延边牛肌肉脂肪代谢中的作用

脂肪沉积是家畜的重要经济性状。然而，很难通过基于性状的牛育种来遗传改善肌内脂肪沉积。本研究的主要目的是分析影响牛肉风味的因素，并检测与延边牛肌肉内脂肪沉积相关的功能性microRNA（miRNA，miR）。来自六头公牛的背最长肌样本被分为高脂肪组和低脂肪组（n = 3 个）基于大理石花纹分数，并使用 miRNA 测序进行转录组分析。共发现 33 个 miRNA 和 38 个基因在高脂肪和低脂肪组中差异表达。进行定量实时聚合酶链反应以验证测序结果。整合的 miRNA-mRNA 分析表明，miRNA 相关的靶基因主要与骨骼肌发育相关。然而，一些 miRNA（miR-424 等）和基因（ATF3等）也与脂肪代谢有关。miR-22-3p 和WFIKKN2之间的靶向关系基因及其参与脂肪细胞分化的实验证实。该研究结果可能为选择具有改善肉质的牛提供潜在的候选分子靶标。