Effect of minor allele SNPs on PBEF promoter activity in cytokine-stimulated endothelium. Measurements of T-1543T- or C-1543C-pGL-3 basic vector firefly luciferase activity were performed in transiently transfected HMVEC-L. T-1543T- or C-1543C-pGL-3 basic vector firefly luciferase reporter constructs were cotransfected with luciferase controls into HMVEC-L for 4 hours. Cell lysates were harvested for luciferase activity assay. Renila luciferase activity was assayed as a base for the transfection efficiency normalization. The activity was expressed as relative light unit. Whereas the GG genotype T-1001G promoter failed to alter PBEF luciferase activity, the CC genotype in the PBEF promoter T-1543C decreased luciferase reporter gene expression (1.80 decrease, n = 6, p <0.01) relative to controls (n = 6). *, P <0.01. The C-1543T SNP alters PBEF expression, potential mechanism of protection from ALI in Caucasians.