Identification and Characterization of Circular RNAs in Association With the Deposition of Intramuscular Fat in Aohan Fine-Wool Sheep

Le Zhao; Lisheng Zhou; Xiaojing Hao; Lei Wang; Fuhui Han; Lirong Liu; Xinming Duan; Feng Guo; Jianning He; Nan Liu

doi:10.3389/fgene.2021.759747

Identification and Characterization of Circular RNAs in Association With the Deposition of Intramuscular Fat in Aohan Fine-Wool Sheep

Front Genet. 2021 Dec 6:12:759747. doi: 10.3389/fgene.2021.759747. eCollection 2021.

Authors

Le Zhao¹, Lisheng Zhou¹, Xiaojing Hao², Lei Wang¹, Fuhui Han¹, Lirong Liu³, Xinming Duan⁴, Feng Guo⁵, Jianning He¹, Nan Liu¹

Affiliations

¹ College of Animal Science and Technology, Qingdao Agricultural University, Qingdao, China.
² Qingdao Animal Husbandry and Veterinary Research Institute, Qingdao, China.
³ China Animal Health and Epidemiology Center, Qingdao, China.
⁴ Nongfayuan Zhejiang Agricultural Development Co. Ltd., Huzhou, China.
⁵ Tongliao Animal Agriculture Development Service Center, Tongliao, China.

Abstract

Aohan fine-wool sheep (AFWS) is a high-quality fine-wool sheep breed that supplies wool and meat. Research is needed on the molecular mechanism behind intramuscular fat (IMF) deposition that greatly improves mutton quality. The widely expressed non-coding RNA is physiologically used in roles such as competitive endogenous RNA (ceRNA) that includes circular RNAs (circRNAs). Although circRNAs were studied in many fields, little research was devoted to IMF in sheep. We used the longissimus dorsi muscle of 2 and 12-month-old AWFS as research material to identify circRNAs related to IMF deposition in these sheep by RNA-seq screening for differentially expressed circRNAs in the two age groups. A total of 11,565 candidate circRNAs were identified, of which the 104 differentially expressed circRNAs in the two age groups were analyzed. 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). The differentially expressed circRNAs included ciRNA455, circRNA9086, circRNA7445, circRNA4557, and others. The source genes involved in these pathways might regulate IMF deposition. We used the TargetScan and miRanda software for interaction analysis, and a network diagram of circRNA-miRNA interactions was created. CircRNA455-miR-127, circRNA455-miR-29a, circRNA455-miR-103, circRNA4557-mir149-5p, and circRNA2440-mir-23a might be involved in the IMF deposition process. The targeting relationship of circRNA4557-miR-149-5p was verified by a dual-luciferase reporter assay. The RT-qPCR results of seven randomly selected circRNAs were consistent with the sequencing results. This study provides additional information on circRNA regulation of IMF deposition in AFWS and is a useful resource for future research on this sheep breed.

Keywords: aohan fine-wool sheep; circular RNA; interaction analysis; intramuscular fat; regulatory mechanism.