Promoter activity of the mvWF 5′ flanking region, first exon, and first intron in various cell lines. The mvWF promoter fragments were coupled to the luciferase reporter gene and named according to the scheme shown (upper left). Nonendothelial cells (NIH 3T3 and HEK) and endothelial cells (Py-4-1, CPAE, and BAEC) were transiently transfected with the mvWF luciferase constructs and harvested 24 hours later for luciferase activity. The results show the mean and standard deviation of luciferase light units obtained in triplicate from 1 representative experiment. More than 3 independent experiments were performed with each cell line. Luciferase light units are corrected both for transfection efficiency (as described in Materials and Methods) and for the activity of a promoterless PGL2-Basic vector.