The basis for the endothelial cell-restricted expression of endothelial nitric-oxide synthase
(eNOS) is not known. While transgenic promoter/reporter mice demonstrated endothelium
cell-specific eNOS expression, we found robust expression of episomal eNOS
promoter/reporter constructs in cell types that do not express the native eNOS transcript. To
explore the mechanism underlying this differential activity pattern of chromatin-versus
episome-based eNOS promoters, we examined the methylation status of 5′-regulatory …