MiR-3594-3p regulates proliferation and differentiation in myoblasts of chickens by targeting APOBEC2

MicroRNAs (miRNAs) play a pivotal role in muscle development. To identify miRNAs associated with myofiber formation during chicken embryogenesis, two chicken strains with distinct genetic backgrounds were selected—Rose-comb chicken and Cobb chicken for our experiments. Leg muscles from Rose-comb and Cobb chicken embryos at days 8 (E8) and 14 (E14) of incubation were collected for immunohistochemical analysis and small RNA sequencing to screen for differentially expressed miRNAs, which were subsequently validated by qRT-PCR. Softwares were employed to predict miRNA target genes, and miRNA-mRNA co-analysis was conducted to identify miRNA-mRNA interaction pairs related to myofiber formation. The differentially expressed miRNA-3594-3p and its target gene, APOBEC2, were identified. Subsequently, functional validation of the gene was conducted. Results demonstrated that miR-3594-3p overexpression during the proliferation phase significantly inhibited myoblast growth, a phenotype recapitulated by APOBEC2 knockdown. During differentiation, miR-3594-3p upregulation enhanced expression of myogenic regulatory factors (MYOG, MYOD, MYHC) and slow-twitch muscle markers (TNNT1, TNNC1), while markedly repressing fast-twitch muscle genes (TNNC2, TNNT3). Notably, APOBEC2 suppression mirrored these effects, confirming miR-3594-3p’s role in modulating myoblast proliferation, differentiation, and muscle fibrin isoform switching through APOBEC2 regulation. This work elucidated miRNA-mediated regulatory networks governing embryonic muscle development in poultry, offering mechanistic insights with translational potential for improving meat quality traits in agricultural genetics.