Fig. 6.

N6-methyladenosine modification mediates circYthdc2 translation polypeptides. A Upper panel: Schematic diagram of Flag-circYthdc2-m⁶A-mut plasmid construction. Lower panel: MKC cells were transfected with Flag-circYthdc2 or Flag-circYthdc2-m⁶A-mut plasmids, after 48 h, the immunoblot analysis was performed. B Myc-STING and Flag-circYthdc2 were cotransfected into MKC cells with m⁶A modification-related genes, respectively, and then the protein levels of Myc-STING and Flag-circYthdc2 were detected. C Left panel: Myc-STING and Flag-circYthdc2 were cotransfected into MKC cells with METTL3 or METTL14, respectively, and then the protein levels of Myc-STING and Flag-circYthdc2 were detected. Middle panel: Myc-STING and Flag-circYthdc2 were cotransfected into MKC cells with FTO or YTHDF1, respectively, and then the protein levels of Myc-STING and Flag-circYthdc2 were detected. Right panel: Myc-STING and Flag-circYthdc2 were cotransfected into MKC cells with YTHDF3 or Ythdc2, respectively, and then the protein levels of Myc-STING and Flag-circYthdc2 were detected. D Relative RNA levels of circYthdc2 in MKC cells after transfected with pcDNA3.1, METTL3, METTL14, YTHDF1, YTHDF3, FTO, and Ythdc2, respectively. E The m⁶A level alteration of circYthdc2 upon METTL3 or FTO overexpression was examined by MeRIP-qPCR. MKC cells were transfected with vector or METTL3 or FTO plasmid for 48 h. F The level of circYthdc2 upon YTHDF1 or YTHDF3 or Ythdc2 overexpression were examined by RIP-qPCR. MKC cells were transfected with vector or YTHDF1 or YTHDF3 or Ythdc2 plasmid for 48 h. G The protein level of YTHDF1 or YTHDF3 or Ythdc2 was examined by RNA pulldown. MKC cells were transfected MS2-GFP, MS2-circYthdc2 or MS2-circYthdc2-m⁶A-mut with vector or YTHDF1 or YTHDF3 or Ythdc2 plasmid for 48 h. H Relative luciferase activities were detected in MKC after cotransfection with STING expression plasmid, pRL-TK Renilla luciferase plasmid, luciferase reporters, circYthdc2, METTL3, METTL14, FTO, YTHDF1, YTHDF3. I Coimmunoprecipitation analysis of STING ubiquitination in MKC cotransfected with Myc-STING, Flag-circYthdc2 or m⁶A modification-related genes expression plasmid and HA-ubiquitin-WT, HA-ubiquitin-K11 or HA-ubiquitin-K48 plasmids. All data represented the mean ± SE from three independent triplicated experiments. *, p < 0.05; **, p < 0.01