Identification and characterization of circRNAs in the deposition of intramuscular fat in Aohan fine-wool sheep

Abstract Background Aohan fine-wool sheep (AFWS) is a high-quality fine-wool sheep breed that supplies both wool and meat. The quality of its meat is affected by many factors. Research is needed on the molecular mechanism of intramuscular fat (IMF) growth, which greatly improves mutton quality. The widely expressed non-coding RNA is used in roles such as competitive endogenous RNAs (ceRNAs), including microRNAs (miRNAs). Although circular RNA (circRNA) was studied in many fields, little research was devoted to IMF in sheep. We used RNA-Seq to analyze tissues associated with IMF in 2-month-old and 12-month-old AFWS rams to understand the role of circRNA in the growth and development of sheep IMF. Results A total of 11,565 candidate circRNAs were identified, of which 104 were differentially expressed in the two age groups. We analyzed these differentially expressed circRNAs. Enrichment analysis was performed using Gene Ontology and the Kyoto Encyclopedia of Genes and Genomes. The enriched pathways included lipid transport (GO:0006869), negative regulation of canonical Wnt signaling pathway (GO:0090090), fat digestion and absorption (ko04975), and sphingolipid metabolism (ko00600). We used the TargetScan and miRanda software programs for interaction analysis, and a network diagram was created. Six circRNAs were randomly selected and verified the RNA-Seq results by quantitative real-time PCR. Conclusion This study provides more information on circRNA regulation in AFWS, and is a useful resource for further research on this sheep breed.