Research Paper Volume 1, Issue 9 pp 803—817

Figure 2. TTP promotes p53 expression through protein stabilization. (A) HeLa Tet-Off/TTP-Flag cells grown in presence or absence of Dox for 48 hr (left panel) and HeLa cells infected with AdGFP or AdGFP/TTP virus for 48 hr (right panel) were examined for TTP and p53 expression by western blotting. Actin was used as a loading control. (B) RT-PCR analysis of p53 mRNA expression in HeLa Tet-Off/TTP-Flag cells grown in presence or absence of Dox for 48 hr. Induction TTP-Flag mRNA is shown along with loading control GAPDH. (C) TTP promotes increased stability of p53 protein. HeLa Tet-Off/TTP-Flag cells grown in presence (- TTP) or absence (+ TTP) of Dox for 48 hr were incubated with 20 μg/ml cycloheximide (CHX) to inhibit protein synthesis for the indicated times. Decay of p53 protein was examined by western blot (left panels) using actin as a loading control. Decay curves of p53 protein (right panel) in the presence (open circles) and absence (filled circles) of TTP was obtained by western blot analysis and normalized to the internal control actin.