METTL3 and obesity due to melanocortin 4 receptor deficiency: Concordantly, IFN expression was impaired by METTL3 knockout, with lower levels of m6A of cGAS, p204 and Sting144 as well as Irf3.145 Reciprocally, METTL3 activity can be enhanced by its phosphorylation of S67 mediated by the STING–TBK1 axis, which underlying a positive feedback circuit.145 As an m6A eraser, fat mass and obesity-associated (FTO) knockdown leads to increased IFN expression in HSV-1 infection.144