The EDN promoter/intron combination is active in HL60 cells and their differentiated derivatives. HL60, HL60 7.7, and HeLa cells (10 × 106 per transfection) were transfected with a CAT reporter construct containing the EDN promoter and the first intron (EDN-CAT; 20 μg), the empty vector without EDN sequences (pBLCAT3; 20 μg), or a positive control containing the promoter of the β-actin gene (β actin-CAT; 20 μg) by electroporation (HL60 cells, 280 V, 960 μF) or calcium phosphate precipitation (HeLa cells). Some cells received BA (0.5 mmol/L) 1 hour after transfection (HL60 7.7/BA). Two days posttransfection, cells were harvested and assayed for CAT activity. Bars indicate the mean percentage of acetylation of at least four independent experiments. The standard deviation is indicated by error bars. The EDN reporter construct is clearly active in HL60 cells and their differentiated derivatives, but not in nonhematopoietic HeLa cells.
