Characterization of the circRNA–miRNA–mRNA Network to Reveal the Potential Functional ceRNAs Associated With Dynamic Changes in the Meat Quality of the Longissimus Thoracis Muscle in Tibetan Sheep at Different Growth Stages

Abstract

Circular RNAs (circRNAs) have a regulatory role in animal skeletal muscle development. In this study, RNA sequencing was performed to reveal the temporal regularity of circRNA expression and the effect of the circRNA–miRNA–mRNA ceRNA regulatory network on the meat quality of longissimus thoracis (LT) muscle in Tibetan sheep at different growth stages (4 months old, 4 m; 1.5 years old, 1.5 y; 3.5 years old, 3.5 y; 6 years old, 6 y). There were differences in the carcass performance and meat quality of Tibetan sheep at different ages. Especially, the meat tenderness significantly decreased (p < 0.05) with the increase of age. GO functional enrichment indicated that the source genes of the DE circRNAs were mainly involved in the protein binding, and myofibril and organelle assembly. Moreover, there was a significant KEGG enrichment in the adenosine 5′-monophosphate (AMP)-activated protein kinase (AMPK) signaling pathway, as well as the calcium signaling pathway, regulating the pluripotency of the stem cells. The circRNA–miRNA–mRNA ceRNA interaction network analysis indicated that circRNAs such as circ_000631, circ_000281, and circ_003400 combined with miR-29-3p and miR-185-5p regulate the expression of LEP, SCD, and FASN related to the transformation of muscle fiber types in the AMPK signaling pathway. The oxidized muscle fibers were transformed into the glycolytic muscle fibers with the increase of age, the content of intramuscular fat (IMF) was lowered, and the diameter of the muscle fiber was larger in the glycolytic muscle fibers, ultimately increasing the meat tenderness. The study revealed the role of the circRNAs in the transformation of skeletal muscle fiber types in Tibetan sheep and its influence on meat quality. It improves our understanding of the role of circRNAs in Tibetan sheep muscle development.

A genome-wide landscape of mRNAs, lncRNAs, circRNAs and miRNAs during intramuscular adipogenesis in cattle

“…The number of circRNAs annotated in this study was much higher than annotated in similar studies in bovine muscle tissue (1318 ciRNAs and 5177 circRNAs) [ 30 , 31 ] and higher than the sequencing results of porcine subcutaneous adipocyte differentiation (8623 circRNAs) [ 21 ]. However, it is close to the recent circRNA-seq results of sheep muscle (11,749 circRNAs) [ 32 ]. In terms of the observed distribution of ncRNA types, the numbers of intergenic lncRNAs and canonical circRNAs accounted for the largest proportions of lncRNAs and circRNAs, respectively, and were similar to the results during porcine subcutaneous fat differentiation [ 21 ] and in line with the general rule [ 33 , 34 ].…”

Comparative Transcriptome Analysis Reveals the Mechanism Associated With Dynamic Changes in Meat Quality of the Longissimus Thoracis Muscle in Tibetan Sheep at Different Growth Stages

“…A total of 16 healthy female Tibetan sheep were selected from the same flock of the Haiyan County, Qinghai Province, China, including 4 months ( n = 4), 1.5 years ( n = 4), 3.5 years ( n = 4), and 6 years ( n = 4). For the detailed samples collection process, see our previous study ( 19 ). Then, the initial weight, hot carcass weight, and dressing percentage were recorded and the meat quality were determined.…”

“…Then, the initial weight, hot carcass weight, and dressing percentage were recorded and the meat quality were determined. The sample collection and processing for RNA extraction were carried out according to the results of our previous study ( 19 ).…”

Coevolution of Rumen Epithelial circRNAs with Their Microbiota and Metabolites in Response to Cold-Season Nutritional Stress in Tibetan Sheep

“…If the alignment positions of the two anchor points were in the opposite direction linearly, the reads of the anchor points were extended until the binding position of the circRNAs was found. If the sequences on both sides at this time were GT/AG splicing signals [ 19 ], they were judged as circRNAs.…”