Fig. 5: METTL14 R255 methylation stabilizes the methyltransferase complex to its substrate RNA.

a Western blot of methyltransferase complex components METTL3, METTL14 and WTAP proteins in WT and METTL14 R255K mESCs. Representative figures of two independent replicates are shown. b Western blot showing the subcellular ___location of METTL3, METTL14, and WTAP proteins in WT and METTL14 R255K mESCs. WCL whole cell lysate, C cytoplasmic fraction, N nuclear fraction. Representative figures of two independent replicates are shown. c Co-IP showing the interaction of METTL3 with SFB-tagged METTL14 or METTL14 R255K in HeLa cells. Representative figures of four independent replicates are shown. d Co-IP showing the interaction of MYC-WTAP and METTL3 with SFB tagged METTL14 or METTL14 R255K. The experiment was performed once in HeLa cells. SFB-GFP served as a control in (c) and (d). e qPCR showing the binding between METTL14 or METTL14 R255K and RNA with m⁶A downregulated or other m⁶A peaks. Enrichment was normalized against Gapdh. Data are mean ± s.d. from three independent experiments. Two-sided Student’s t-test. f Western blot showing METTL14 or METTL14 R255K protein pulled down by ssRNA probe containing RRACH domains. Representative figures of three independent replicates are shown. Source data for (a–f) provided as a Source Data file. g Proposed model showing the mechanism of METTL14 R255 methylation affecting the deposition of m⁶A methylation on mRNA. R255, arginine 255; R255(me), methylated arginine 255.