Figure 4.

AP-1-mediated DNp73 depletion occurs via the PAOX-antizyme pathway. (a) Effect of overexpressing AP-1 members on the expression of Az1 mRNA and processed Az, [Az1(p)], was assessed by semi-quantitative RT-PCR and immunodetection, respectively, 24 h after transfection in H1299 cells. (b and c) Effect of the AP-1 members on transfected DNp73β in the presence of the naturally occurring antizyme inhibitor, AZI (b) or Flag-tagged PAOX (c) was determined by immunoblot analysis, 24 h after transfection in H1299 cells. Lower panels show quantification of DNp73 from the respective lanes from the blots above (b). (d and e) Effect of siRNA-mediated silencing of paox in the presence of AZI (d) or Az1 siRNA (e) on co-transfected DNp73β levels was determined by immunoblotting 24 h and 48 h after transfection in H1299 cells, respectively. Knockdown efficiency was determined by semi-quantitative RT-PCR