Increased apoptotic cell death in populations of Z+ Jurkat cells transfected with wild-type p53 expression plasmid.

(A) FACS analysis of populations of Z− and Z+ cells transfected with either p53N or p53W. Z+ cells transfected with p53W expression plasmid demonstrated a relative increase in cells staining with both propidium iodide and annexin-FITC antibody (quadrant 3) relative to Z+ cells transfected with p53N expression plasmid or Z− cells transfected with either p53W or p53N expression plasmids. (B) Cell death determined by staining with either propidium iodide (PI) or annexin-FITC antibody (AN) was increased in Z+ cells after transfection of p53W expression plasmid, but it was not increased in Z+ cells transfected with p53N expression plasmid or in Z− cells transfected with either p53N or p53W expression plasmids. Percentage of cells staining with either marker was normalized using equivalent cells transfected with a control plasmid (pCMV5) under identical conditions. In this analysis a ratio of greater than 1.0 indicates increased cell death relative to control, whereas a ratio of less than 1.0 indicates decreased cell death relative to control. (C) Cell death (percentage of cells staining with propidium iodide [PI] per 2000 analyzed cells) was similar in Z− and Z+ cells 24 hours after transfection of p53W expression plasmid, but significantly greater (P < .05 indicated) 48 hours after transfection in Z+ relative to Z− cells. During this interval, normalized p53-dependent transcription of pG¹³PYluc (inset) increased significantly in Z+ cells (*P < .05 for normalized luciferase activity levels 18 and 36 hours after transfection of p53W and reporter genes into Z+ cells).