Fig. 4.

Regulation of p53 binding and localization by the p53 mimetic sequence. (A) Mutations of the putative p53 mimetic sequences were introduced into full-length MDMX and coexpressed with p53 in H1299 cells. MDMX-p53 binding was analyzed by IP-Western blot. (B) U2OS was cotransfected with p53-response reporter BP100-luciferase and MDMX mutants. Endogenous p53 activity was measured by luciferase assay and normalized to cotransfected CMV-lacZ. (C) U2OS cells were transiently transfected with MDMX mutants and stained for MDMX localization by using 8C6 immunofluorescence. (D) Beads loaded with GST-p53 were incubated with H1299 lysate expressing MDMX mutants. p53 binding to MDMX mutants was determined by Western blot.