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. 2012 Jul 9;122(8):2898–2910. doi: 10.1172/JCI63103

Figure 3. p53 induces TACE expression to promote keratinocyte differentiation.

Figure 3

(A) Western blot analyses of p53-deficient and control keratinocytes treated with 2 mM Ca2+ for 48 hours. Lack of p53 impairs expression of TACE, NICD, Keratin 1, and p21. (B) Western blot analyses of WT mouse keratinocytes upon siRNA-mediated TACE (siTACE) or scrambled (siScr) knockdown followed by 48 hours of 1 mM Ca2+ treatment. Expression of TACE, NICD, and Keratin 1 is TACE dependent. (C) Western blot analyses of human primary keratinocytes upon siRNA-mediated TACE or scrambled knockdown after 48 hours of 1 mM Ca2+ treatment. Expression of TACE, NOTCH1 (NICD), and Keratin 1 is TACE-dependent. (D) TACE promoter contains a p53-binding site. RT-PCR analyses from p53 ChIP in 2 mM Ca2+-induced differentiation conditions (lower panel). (E) Quantitative RT-PCR upon p53 ChIP on the TACE promoter as in Figure 1D. (F) Luciferase reporter activity assay with TACE promoter construct. Increasing concentrations of WT p53 or p53-ER plus 1 μM 4-OH Tamoxifen induce TACE reporter activity, whereas mutant p53 (p53 mut) does not.(G) qRT-PCR analyses of p53-deficient keratinocytes infected with retroviruses overexpressing H-RasV12 or empty vector after 6 days. p53 absence impairs expression of TACE, Notch1, Keratin 1, and p21. *P < 0.05. (H) Western blot analyses of p53-deficient keratinocytes infected with retroviruses overexpressing H-RasV12 or empty vector after 6 days. p53 absence impairs TACE, NICD, Keratin 1, and p21 expression.