HUMAN VON-WILLEBRAND-FACTOR GENE-SEQUENCES TARGET EXPRESSION TO A SUBPOPULATION OF ENDOTHELIAL-CELLS IN TRANSGENIC MICE

The present study was undertaken to define the 5' and 3' regulatory se quences of human von Willebrand factor gene that confer tissue-specifi c expression in vivo Transgenic mice were generated bearing a chimeric construct that included 487 bp of 5' flanking sequence and the first exon fused in-frame to the Escherichia coli lacZ gene. In situ histoch emical analyses in independent lines demonstrated that the von Willebr and factor promoter targeted expression of LacZ to a subpopulation of endothelial cells in the yolk sac and adult brain. LacZ activity was a bsent in the vascular beds of the spleen, lung, liver, kidney, testes, heart, and aorta, as well as in megakaryocytes. In contrast, in mice containing the lacZ gene targeted to the thrombomodulin locus, the 5-b romo-4-chloro-3-indolyl beta-D-galactopyranoside reaction product was detected throughout the vascular tree, These data highlight the existe nce of regional differences in endothelial cell gene regulation and su ggest that the 733-bp von Willebrand factor promoter may be useful as a molecular marker to investigate endothelial cell diversity.