DTWD1 is a target of p53. (A) Four fragments of candidate DTWD1 promoter including F1-R1, F1-R2, F2-R1 and F3-R2 were cloned to construct luciferase reporter system. (B) The effect of luciferase reporter driven by different DTWD1 fragments in (A) was determined by luciferase activity assay. (C) The effect of p53 depletion on DTWD1 expression in GES-1 was determined by real-time RT-PCR. The asterisk indicates statistical significance (p < 0.05, Student’s t test). (D) The effect of p53 overexpression on DTWD1 expression in SGC7901 was determined by real-time RT-PCR. The asterisk indicates statistical significance (p < 0.05, Student’s t test). (E) The binding of p53 to the DTWD1 gene was determined by ChIP assay. The effect of VP16 on DTWD1expression (F) and p53 expression (G) in HCT116 or HCT116 p53-/- cells were determined by real-time RT-PCR and Western blotting, respectively. Asterisks indicate statistical significance (p < 0.05, Student’s t test).