Figure 4.

Further validation of novel p53-target genes. (a) Colon carcinoma HCT116 cells were treated with nutlin3a and the level of expression of 18 novel p53-target genes was assessed by qPCR. (b) The protein level of aurora kinase A was decreased upon p53 activation by nutlin3a, RITA and 5-FU in MCF7, as well as HCT116 cells, as assessed by immunoblotting. (c) Changes of mRNA levels of 18 selected genes were assessed by qPCR upon overexpression of p53 in the p53 null HCTTP53−/− cells. (d) Schemes depicting p53-bound fragments derived from the p53-induced SEI1 and p53-repressed AURKA promoters, which were cloned into a luciferase reporter plasmid. (e) The activity of luciferase reporter expressed under the control of AURKA and SEI1 promoters was assessed upon ectopic expression of p53 in HCTTP53−/− cells