Figure 1. Hzf induction in response to various stresses modulates p53 transcriptional function.

(A) Hzf is induced by genotoxic and oxidative stress in a p53-dependent manner. HCT116, HCT116 p53^−/−, U2OS and LNCaP cells were treated with etoposide (ETO, 40 μM), IR (4 Gy) or H₂O₂ (0.4 mM) for the indicated time points. The cells were then harvested, and northern blots or western blots were carried out.

(B) Loss of Hzf represses p21 induction but enhances Bax expression in response to DNA damage or ectopic p53. U2OS and EJ cells were treated with etoposide (ETO, 40 μM) or infected with Ad-p53 respectively for 24 hours. The cells were then harvested and Western blots carried out for the indicated proteins.

(C) Wt and Hzf^−/− MEFs were treated with etoposide (ETO, 40 μM) for 24 hours. The cells were then harvested and Northern blots carried out as indicated.

(D) Effects of Hzf inhibition on p53-mediated transcription. Reporter gene constructs containing the p53-responsive elements (pGL3-p21-Luc or pGL3-Bax-Luc) or control vector alone (pGL3-Basic) were co-transfected into U2OS and Saos2 cells with either Hzf shRNA or control scrambled shRNA, and 24 hours later cells were treated with etoposide or infected with Ad-p53 for another 24 hours. At the end of the time point Luciferase assay was carried out. Error bars are means ± SD of three independent experiments with duplicate samples.