Fig. 5: METTL1 induces the m7G modification of ATF4 mRNA.

A Volcano plot of significantly altered mRNA in METTL1-knockdown HSC-1 cell compared to control cell. B Differentially expressed genes (DEG) were clustered and shown in a heat map of RNA sequencing. C, D qRT-PCR was performed to detect the downregulated DEG in HSC-1 and A431 cells (n = 6). E Suppressed m7G methylated ATF4 mRNA in METTL1-knockdown cells was detected by MeRIP-qPCR (n = 3). F qRT-PCR showing ATF4 mRNA transcripts stability in ActD-treated HSC-1 and A431 cells transfected with or without shMETTL1 (n = 3). G The protein levels of ATF4 in HSC-1 and A431 cells with or without shMETTL1 were detected by western blot (n = 3). β-Tubulin was used for the normalization control. H The mRNA levels of ATF4 in cells transfected with WT METTL1 or Mut METTL1 were assessed by qRT-PCR (n = 6). I qRT-PCR showing ATF4 mRNA transcripts stability in ActD-treated HSC-1 and A431 cells transfected with WT METTL1 or Mut METTL1 (n = 3). J The protein levels of ATF4 in cells transfected with WT METTL1 or Mut METTL1 were assessed by western blot (n = 3). β-Tubulin was used for the normalization control. K The protein levels of METTL1 and ATF4 in normal specimens (n = 7) and cSCC tumors (n = 36) with different tumor grade were detected by IHC on continuous sections. The intensity optical density (IOD) for each sample was calculated. L Scatter plots showing the positive correlation between METTL1 and ATF4 expression in cSCC tumors. Data are shown as mean ± SEM. *P < 0.05, **P < 0.01, ***P < 0.001.