Role of Pirh2 in Mediating the Regulation of p53 and c-Myc
Figure 1
Pirh2 Negatively Regulates p53 Turnover in Response to DNA Damage.
(A) Time course immunoblot analysis of the expression of p53, p21, Bax, Puma and Pirh2 in response to irradiation (6 Gγ) of Wt and Pirh2−/− splenocytes. p53 level was quantified based on scanning by densitometry using ImageJ and normalized by β-actin level. p53 fold increase is indicated. Data are representative of four independent experiments. (B) Splenocytes from Wt and Pirh2−/− mice were IR treated (6 Gγ) and their RNA extracted at time 0, 1 and 4 h post-IR. Quantitative RT-PCR analysis was performed to assess gene expression of Puma and p21 and was normalized to actin mRNA. Fold changes of mRNA expression in Wt and Pirh2−/− compared to their time 0 h is shown. Student's t test was used for statistical analysis. P<0.001 for time 0 h vs. 1 h or 4 h for Wt (n = 4) and Pirh2−/− (n = 5). Error bars represent SD. (C) Wt and Pirh2−/− 6–8 week-old mice were irradiated (6 Gγ), sacrificed at different times post-IR and the level of p53 expression in spleen was examined by IHC. Data are representative of three independent experiments. (D) p53 positive cells from spleen (upper panel) and thymus (lower panel) of untreated (n = 3) and irradiated (n = 3) mice were counted from 10 different fields for each time point. Student's t test was used for statistical analysis. *: P<0.05. Error bars represent SD.