To elucidate the mechanism how MTR4 regulates AS in HCC cells, we focused on the key glycolytic genes GLUT1 and PKM2, both are MTR4 targets as confirmed by the presence of MTR4 binding motifs in their pre-mRNAs and by the standard RIP assays, indicating that MTR4 binds to the intronic regions of pre-mRNAs of these genes (Fig. 4b–e). This evidence concerns the gene MTREX and hepatocellular carcinoma.