Expression of mutant NE activates UPR-induced apoptosis in promyelocytes. Cultured human promyelocytes were transiently transfected with vector alone (GFP) or the indicated NE cDNA. (A) BiP mRNA expression relative to rRNA was determined on sorted GFP⁺ cells 12 hours after transfection. (B,C) Representative scatter plots of annexin V expression on cells transfected with WT (B) or G185R NE (C); data are gated on GFP⁺ 7AAD⁻ cells. Gates were set based on untransfected cells (not shown). (D) The percentage of GFP⁺ 7AAD⁻ cells that were annexin V⁺ at 24 hours after transfection is shown. Data are normalized to WT-transfected cells, where the percentage of annexin V⁺ cells was defined as 1. (E) CHOP mRNA expression relative to rRNA was determined on sorted GFP⁺ cells 12 hours after transfection. Data represent the mean (± SD) of 4 to 6 independent experiments * P < .05 compared with WT-transfected cells.