Figure 3.
(A) p53 stabilization and activity following UVR is time-of-day dependent in mouse skin. SKH-1 hairless mice kept under LD12:12 cycle were irradiated with 300 J/m2 of UV at either ZT21 (4AM) or ZT09 (4PM) and sacrificed at the indicated time points. Protein lysates were then prepared for immunoblotting. The non-specific signal from an unknown protein that cross-reacts with anti-Mdm2 antibody (NS) was used as an internal control. (B-D) Quantitative analysis of p53, P21, and Mdm2 protein levels in the mouse skin, respectively, from two independent experiments. Error bars represent means ± standard deviations (SD) (n=2 mice at each time point). (E) Circadian oscillation of p53 and Mdm2 proteins in mouse skin. C57BL/6 mice kept under a DD12:12 cycle for 24 hrs were sacrificed at the indicated circadian times and the levels of the indicated proteins were determined from whole skin by immuno-blotting. Note the robust oscillation of the CRY1, p53 and Mdm2proteins. Ponceau Stain was used as a loading control. N=2 mice at each time point. (F) Quantitative analysis of CRY1, p53 and Mdm2 protein levels in the mouse skin, respectively, from E and another experiment (not shown). R.U: relative unit.