Stage-specific requirement for METTL3-dependent m6A epitranscriptomic regulation during myogenesis

The regulatory role of N⁶-methyladenosine (m⁶A) modification in skeletal muscle myogenesis and muscle homeostasis remains poorly characterized, particularly regarding the functional significance of methyltransferase-like 3 (METTL3), the catalytic subunit of the m⁶A methyltransferase complex (MTC), in myogenic regulation. Through systematic investigation of m⁶A epitranscriptomic remodeling during myogenesis, we demonstrate that METTL3-mediated m⁶As orchestrates myoblast fusion processes in both differentiation and regeneration contexts. Notably, we observed marked induction of Mettl3 expression post-injury, accompanied by substantial transcriptomic alterations in myogenesis-related pathways. High-resolution m⁶A mapping revealed distinct dynamic patterns of METTL3-regulated m⁶As during differentiation, exhibiting dichotomous regulation across target transcripts. Mechanistically, we identified myogenic fusion factors Mymx and Mymk as direct targets of METTL3, showing concomitant upregulation of both transcript abundance and m⁶A deposition during myogenesis. This study provides comprehensive multi-omics resources delineating the mechanistic landscape of METTL3-regulated m⁶As in myogenic programming, establishing METTL3 as a critical regulatory node governing myoblast fusion dynamic.