Fig. 4

ATRX expression levels measured by reverse transcription-quantitative PCR after irradiation and siRNA transfection assays. A and B ATRX expression levels were significantly increased following irradiation in U-251MG cells, and the expression levels peaked at 24 h after radiation. Relative ATRX/GAPDH mRNA expression levels were defined as the ratio of normalized ATRX mRNA levels in the experimental group to the control group. C and D Transfection efficiency of siRNA 1–3 reached 90–60% in U-251MG cells. Transfection efficiency of siRNA 1–3 reached 28–59% in LN229 cells. E and F ATRX expression levels were not increased in all four siRNA groups in U-251MG and LN229 cells following irradiation. *P < 0.05, **P < 0.01, ***P < 0.001. siRNA, small interfering RNA; ATRX, alpha-thalassemia X-linked mutant retardation syndrome