Fig. 4.

The mut-p53 regulates the transcription of CTSL depended on Egr-1 activation under IR. a Cells were treated with/ without IR at various time points (0, 6, 12, 24 h). The levels of CTSL and Egr-1 were examined by western blotting (up panel). The corresponding quantities of protein expression were shown (down panel). b Cells were treated as mentioned above and harvested for ChIP assay to verify the interaction between Egr-1 and the promoter of CTSL under/ or not IR (up panel). The corresponding quantities of CTSL promoter expression were shown (down panel). c ChIP assay was analyzed to verify the interaction between p53 and the promoter of Egr-1 in three p53 status cell lines with or without IR treatment. The recruitment of p53 to the Egr-1 promoter was shown (up panel). The corresponding quantities of Egr-1 promoter expression were shown (down panel). d Flag-p53 (R273H) cells were transfected with three Egr-1 si-RNA sequences under IR and total cell lysates were analyzed for Egr-1 and CTSL by western blotting using the indicated antibodies. e Flag-p53 (R273H) cells were transfected with Egr-1 si-RNA sequence under IR and harvested for ChIP assay to verify the interaction between p53 and promoter of CTSL (up panel). The corresponding quantities of CTSL promoter expression were shown (down panel). Data are shown as mean ± S.D., n = 3, *P < 0.05, **P < 0.01, *** P < 0.001, Student’s t-test