Transcriptional regulation of p21 by EIF1AX is p53‐independent. A, The recruitment of EIF1AX to the p21 promoter in p53+/+ HCT‐116 cells. Soluble chromatin from p53+/+ HCT‐116 cells was immunoprecipitated with anti‐EIF1AX, rabbit normal IgG antibody served as control. qRT‐PCR analysis of the final extracted DNA using the primers specific to the proximal promoter region of the p21 gene. B, The recruitment of EIF1AX to the p21 promoter in p53−/− HCT‐116 cells. Soluble chromatin from p53−/− HCT‐116 cells was immunoprecipitated with anti‐EIF1AX, rabbit normal IgG antibody served as control. The final extracted DNA samples were amplified by qRT‐PCR using primers specific to the proximal promoter region of the p21 gene. C, The effect of EIF1AX on p21 promoter activity in p53+/+ HCT‐116 cells. Luciferase assay of p53+/+ HCT‐116 cells transfected with p21‐Luc reporter construct and 0, 0.1, 0.2 and 0.4 µg/well EIF1AX expression construct. D, The effect of EIF1AX on p21 promoter expression in p53−/− HCT‐116 cells. Luciferase assay of p53−/− HCT‐116 cells transfected with p21‐Luc reporter construct and 0, 0.1, 0.2 and 0.4 µg/well EIF1AX expression construct. E, qRT‐PCR analysis of p21 in EIF1AX knock‐down p53+/+ (left panel) and p53−/− (right panel) HCT‐116 cells. F, Western blotting analysis of p21 in EIF1AX knock‐down p53+/+ (left panel) and p53−/− (right panel) HCT‐116 cells. G, Quantification of proteins in (F)