INS and obesity due to melanocortin 4 receptor deficiency: Previous study reported that brown fat‐specific Mettl3 knockout blunted brown fat development and promoted diet induced obesity and systemic insulin resistance in mice.[24] To comprehensively evaluate the in vivo role of Mettl3 specifically on fat biology, we crossed Adiponectin‐Cre with Mettl3‐Loxp mice to obtain a Mettl3 fat‐specific genetic ablation mice model (Mettl3 FKO) (Figure3A; Figure S2A, Supporting Information).