FIG. 5.
Endogenous expression from the ppET-1 promoter. RNA from human target cells, including primary endothelial cells (Primary EC), was isolated and used to amplify regions of the ppET-1 cDNA (+447 to +630), the cDNA derived from the upstream promoter (−60 to +630, based on the same numbering system relative to the endothelial cell-specific transcript [Fig. 1]), or the GAPDH cDNA as a control. Detection of −60 to +630 is more sensitive than of +447 to +630 (compare HT1080 products). Consequently, while it is evident that the ppET-1 promoter is active in HMEC-1 and primary endothelial cells, the +447 to +630 product for EAhy926 cannot be interpreted as such due to the activity of the upstream promoter in these cells.