Vascular endothelial cadherin (VE cadherin) gene encodes a Ca2؉ -dependent cell adhesion molecule required for the organization of interendothelial junctions. This gene is exclusively and constitutively expressed in endothelial cells. Previous data with transgenic mice revealed that the transcriptional regulatory elements present within a ؊2486/؉24 DNA fragment of mouse VE cadherin gene mimic the tissue-specific activity of the endogenous promoter. In this study, we analyzed elements implicated in the function of the proximal regulatory region. Electrophoretic mobility shift assay identified a GT-rich sequence (positions ؊49/؊39) interacting with factors related to the Sp1 family. Point mutations abolished the binding of nuclear proteins in vitro and drastically diminished the activity of the promoter in transient transfection assay. Supershift assays with antibodies against proteins of the Sp1 family revealed that Sp1 and Sp3 interact with this region of the VE cadherin promoter. Furthermore, two GGAA motifs, located at positions ؊93/؊90 and ؊109/؊106, were shown to interact with nuclear factors. Site-directed mutagenesis of these sequences demonstrated that these Ets binding sites are essential for promoter activity. In vitro binding assays in the presence of various antisera suggest that Erg is one of the proteins interacting with the ؊109/؊106 site.

Vascular endothelial-cadherin (VE-cadherin) is a calcium-dependent adhesive molecule, exclusively and constitutively expressed in endothelial cells. Analysis of the VE-cadherin promoter fused to a reporter gene in bovine aortic endothelial cells showed three major functional regions. The proximal region alone (−139, +24) promoted nonspecific transcription; the addition of the (−289, −140) and (−2226, −1190) domains abolished transcription in fibroblasts while expression in endothelial cells remained unchanged, suggesting that fragments (−2226, +24) and longer contain the full endogenous promoter activity. To study the transcriptional specificity of the promoter region in vivo, we generated transgenic mice carrying the chimeric construct containing the (−2486, +24) region. The promoter directed reporter expression in all examined organs of adult transgenic mice. During embryonic development, transgene expression was detected at the early steps of vasculogenesis. Later, the expression persisted during development of the vascular system and was restricted to the endothelial layer of the vessels. Together, these data provide evidence for specific regulatory regions within the VE-cadherinpromoter. Furthermore, the identification of DNA sequences restricting gene expression to the endothelium has many potential applications for the development of animal models of cardiovascular or angiogenic diseases or for the delivery of therapeutic molecules.