Expression of CAT reporter gene constructs containing deletions of the 5′-flanking region of the vWF gene and 19 nt or 244 nt of the first exon. (A) Depicted on the left side of the figures are the vWF promoter-CAT deletion constructs containing 19 nt or 244 nt of the first exon (pGvW vectors) and pSVGCAT-A (containing the SV40 early promoter). Thirty micrograms of the CAT plasmids was transfected into HUVECs in the presence of 0.5 μg of pCMVβ plasmid and 30 μg of carrier plasmid pBS−. Forty-eight hours later, extracts were prepared and the level of CAT activity was measured, normalized for β-galactosidase activity, and expressed relative to the CAT activity of plasmid pGvW(−89/+19). Plasmid pGvW(+244/−89) was transfected into HUVECs as a reference for background CAT activity. The results are the mean ± SD of 4 to 6 experiments. (B) HUVECs and HeLa cells were transfected with the pGvW vectors indicated on the left side as described in the Materials and Methods. The level of CAT activity was measured, normalized for β-galactosidase activity, and expressed relative to the CAT activity of plasmid pGvW(−89/+19). (▪) HUVECs; () HeLa cells.