Fig. 5

METTL1 stabilizes CDK14 mRNA by mediating internal m7G modification. A-B The RNA dot blot assay was performed to detect the different mRNA internal m7G modification levels between CPRC and HSPC cells. Methylene blue was used as a control. C-D Changes in m7G level after METTL1 knockdown, wild or mutant METTL1 overexpression in LNCaP-AI and C4-2 cells. E Flowchart of RNA transcriptome sequencing (RNA-seq) and mRNA internal m7G AlkAniline-Seq in control and METTL1 knockdown LNCaP-AI cells. F Quadrant diagram showing genes with differential mRNA expression (up or down) and significantly altered m7G (hyper or hypo) after METTL1 inhibition. The screening thresholds:|Fold change|>1.5 and p-value < 0.05. G KEGG enrichment analysis of differential genes with down-regulated levels of both mRNA and m7G. H-I RT-qPCR was used to validate the related genes change in the “Transcriptional misregulation in cancer” pathway in LNCaP-AI and C4-2 cells. J-K The CDK14 mRNA internal m7G level was measured by m7G RNA immunoprecipitation assay (MeRIP) using a 10ug m7G specific antibody among groups with different treatments as indicated in CRPC cells lines LNCaP-AI and C4-2. L-M CDK14 mRNA level was detected via RT-qPCR among groups with different treatments as shown. N-O The remaining CDK14 mRNA level in actinomycin D (ACTD) treated LNCaP-AI and C4-2 cells at the indicated time points were measured by RT-qPCR. ***P < 0.001; ****P < 0.0001