Fig. 3.

Binding of cytoplasmic proteins to the p53 3′ UTR is linked to p53 translational up-regulation. (Upper) Schematic of p53 mRNA, depicting U-rich and AU-rich sequences (gray), as well as transcripts (CR and 3′ UTR) used for analysis. (A) REMSA (11) by using either CR or 3′ UTR p53 radiolabeled transcripts and cytoplasmic lysates prepared 4 and 6 h after treatment of RKO cells with either 15 or 30 J/m² UVC. (B) Plasmids pGL3-Luc and pGL3-Luc-p53(3′UTR) were used in transient transfections; 24 h after transfection, cells were either irradiated (15 J/m²) or left untreated, and the relative luciferase activity was calculated 6, 12, and 24 h later.