Identification of Crucial Circrnas in Skeletal Muscle During Chicken Embryonic Development

Abstract

Background: Chicken provides humans with a large amount of animal protein every year, in which skeletal muscle plays a leading role. The embryonic skeletal muscle development determines the number of muscle fibers and will affect the muscle production of chickens. CircRNAs are involved in a variety of important biological processes, including muscle development. However, studies on circRNAs in the chicken embryo muscle development are still lacking. Results: In the study, we collected chicken leg muscles at 14 and 20-day embryonic ages both in the fast- and slow-growing groups for RNA-seq We identified 245 and 440 differentially expressed (DE) circRNAs in the comparison group F14vsF20 and S14vsS20 respectively. GO enrichment analysis for the host genes of DE circRNAs showed that biological process (BP) terms in the top 20 related to growth in F14vsF20 were found such as positive regulation of transcription involved in G1/S phase of mitotic cell cycle, multicellular organismal macromolecule metabolic process, and multicellular organismal metabolic process. In group S14vsS20, we also found some BP terms associated with growth in the top 20 including actomyosin structure organization, actin cytoskeleton organization and myofibril assembly. A total of 7 significantly enriched pathways were obtained, containing Adherens junction and Tight junction. Further analysis of those pathways found three crucial host genes MYH9, YBX3, IGF1R in both fast- and slow-growing groups, three important host genes CTNNA3, AFDN and CREBBP only in the fast-growing group, and six host genes FGFR2, ACTN2, COL1A2, CDC42, DOCK1 and MYL3 only in the slow-growing group. In addition, circRNA-miRNA network also revealed some key regulation pairs such as novel_circ_0007646-miR-1625-5p, novel_circ_0007646-miR-1680-5p, novel_circ_0008913-miR-148b-5p, novel_circ_0008906-miR-148b-5p and novel_circ_0001640-miR-1759-3p. Conclusions: These findings would guide our next research and it would also lay a theoretical foundation for further improving the development mechanism of embryonic skeletal muscle.