Li Bojiang, Feng Chunyu, Zhu Shiyu, Zhang Junpeng, Irwin David M, Zhang Xiaoying, Wang Zhe, Zhang Shuyi
College of Animal Science and Veterinary Medicine, Shenyang Agricultural University, Shenyang, China.
Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada.
Front Genet. 2020 Dec 9;11:587559. doi: 10.3389/fgene.2020.587559. eCollection 2020.
Intramuscular fat (IMF) content is a crucial indicator of meat quality. Circular RNAs (circRNAs) are a large class of endogenous RNAs that are involved in many physiological processes. However, the expression and function of circRNA in IMF in the donkey remains unresolved. Here we performed an expression profiling of circRNAs in the donkey longissimus dorsi muscle and identified 12,727 candidate circRNAs. Among these, 70% were derived from the exons of protein genes. Furthermore, a total of 127 differentially expressed (DE) circRNAs were identified in high (H) and low (L) IMF content groups, including 63 upregulated and 64 downregulated circRNAs. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis of the host genes of the DE circRNAs showed that the host genes were enriched in lipid metabolism related GO terms (e.g., fatty acid beta-oxidation using acyl-CoA dehydrogenase and MLL3/4 complex), and signaling pathways (e.g., TGF-beta and lysine degradation signaling pathway). Further analyses indicated that 127 DE circRNAs were predicted to potentially interact with miRNAs, leading to the construction of circRNA-miRNA regulatory network. Multiple circRNAs can potentially function as sponges of miRNAs that regulate the differentiation of adipocytes. Our results provide valuable expression profile information for circRNA in the donkey and new insight into the regulatory mechanisms of circRNAs in the regulation of IMF content.
肌内脂肪（IMF）含量是肉质的关键指标。环状RNA（circRNAs）是一大类参与许多生理过程的内源性RNA。然而，circRNA在驴IMF中的表达和功能仍未明确。在此，我们对驴背最长肌中的circRNAs进行了表达谱分析，鉴定出12727个候选circRNAs。其中，70%来源于蛋白质基因的外显子。此外，在高（H）和低（L）IMF含量组中总共鉴定出127个差异表达（DE）circRNAs，包括63个上调和64个下调的circRNAs。对DE circRNAs宿主基因的基因本体论（GO）和京都基因与基因组百科全书（KEGG）通路富集分析表明，宿主基因富集在脂质代谢相关的GO术语（如使用酰基辅酶A脱氢酶和MLL3/4复合物的脂肪酸β-氧化）和信号通路（如TGF-β和赖氨酸降解信号通路）中。进一步分析表明，预测127个DE circRNAs可能与miRNAs相互作用，从而构建circRNA-miRNA调控网络。多个circRNAs可能作为调节脂肪细胞分化的miRNAs的海绵发挥作用。我们的结果为驴体内circRNA提供了有价值的表达谱信息，并为circRNAs在调节IMF含量中的调控机制提供了新的见解。
