Integrative microRNA-mRNA Analysis of Muscle Tissues in Qianhua Mutton Merino and Small Tail Han Sheep Reveals Key Roles for oar-miR-655-3p and oar-miR-381-5p.

The Qianhua Mutton Merino (QHMM) is a new variety of sheep () with improved meat performance compared with the traditional Small Tail Han (STH) sheep variety. We recently reported the transcriptome profiling of longissimus muscle tissues between QHMM and STH sheep. In the present study, we aimed to evaluate key micro (mi)RNA-mRNA networks associated with sheep muscle growth and development. We used miRNA sequencing to obtain longissimus muscle miRNA profiles from QHMM and STH sheep. We identified a total of 153 known sheep miRNAs, of which 4 were differentially expressed (DE) between the 2 sheep varieties. We combined these results with mRNA library data to build an miRNA-mRNA network, including 26 target genes of the 4 DE miRNAs. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses showed that 26 target genes were significantly enriched in 86 biological processes, including muscle organogenesis, myoblast migration, cell proliferation, and adipose tissue development, and in 9 metabolic pathways, including carbohydrate, nucleotide, and amino acid metabolic pathways. oar-miR-655-3p and its target gene and oar-miR-381-5p and its target gene were selected for subsequent analysis based on GO and KEGG analyses. The binding sites of oar-miR-655-3p with and oar-miR-381-5p with were validated by a dual-luciferase reporter gene detection system. This represents the first integrative analysis of miRNA-mRNA networks in QHMM and STH muscles and suggests that DE miRNAs, especially oar-miR-655-3p and oar-miR-381-5p, play crucial roles in muscle growth and development.