FIG. 4.

14-3-3σ blocked Mdm2-mediated p53 nuclear export. (A) Subcellular localization of Mdm2 was affected by overexpression of 14-3-3σ. The Rat1-akt cell lines were infected with Ad-HA-14-3-3σ or Ad-β-gal. After 48 h, cells were fixed and stained with anti-Mdm2 to detect the location of Mdm2 (A, D) or stained with anti-HA antibodies to observe the location of 14-3-3σ (B, E). Nuclei were stained with DAPI dye. (B) Activity of 14-3-3σ inhibited Mdm2-mediated p53 nuclear export. R1B/L17 cells were transfected with the indicated constructs to examine the subcellular localization of GFP-p53 as detected by green fluorescence. The cells that received the indicated plasmids were seeded at 2 × 10³ in a chamber slide. The location of GFP-p53 was observed under a fluorescence microscope. A total of 300 cells were counted for the location of GFP-p53 in each condition. The percentages of nuclear-positive cells (N) and nuclear and cytoplasmic-positive cells (N+C) are presented. Data shown were from a typical experiment conducted in triplicate. Bars represent standard deviations.