METTL3-mediated m⁶A modification regulates muscle development by promoting TM4SF1 mRNA degradation in P-body via...

N6-methyladenosine (m⁶A), a well-known post-transcriptional modification, is implicated in diverse cellular and physiological processes. However, much remains unknown regarding the precise role and mechanism of m⁶A modification on muscle development. In this study, we make observation that the levels of m⁶A and METTL3 are markedly elevated during the differentiation phase (DM) compared to the growth phase (GM) in both C2C12 and bovine myoblasts. Notably, deletion of METTL3 decreased m⁶A levels, and promoted myoblast proliferation, inhibited myoblast differentiation in vitro. By performing m⁶A sequencing in both GM and DM myoblast, we further identified that TM4SF1 is involved in m⁶A -regulated muscle development. Mechanistically, METTL3 increases m⁶A-modified TM4SF1 transcripts, and subsequently YTHDF2 promotes TM4SF1 mRNA degradation in P-body through liquid-liquid phase separation (LLPS). Additionally, the rescue experiments in vivo showed that overexpressing METTL3 could rescue the attenuated myogenesis induced by TM4SF1 overexpression during muscle regeneration in mice. Collectively, our findings shed light on a regulatory mechanism by which m⁶A modulates muscle development and raise a new model for m⁶A-mediated mRNA degradation within P-bodies.