CLONING OF THE GATA-BINDING PROTEIN THAT REGULATES ENDOTHELIN-1 GENE-EXPRESSION IN ENDOTHELIAL-CELLS

Previously, we have identified two regions (A and B) of the endothelin-1 promoter that are important for the expression of this gene in cultured vascular endothelial cells. The cis-acting sequence in one of these regions (Region A) includes the core binding motif GATA, raising the possibility that this region of DNA mediates binding of a member of the GATA-binding protein family. In this report, we describe the use of polymerase chain reaction in conjunction with cDNA cloning to characterize the GATA-binding protein expressed in endothelial cells. The nucleotide sequence of endothelial cell cDNA clones is highly homologous to that of the chicken GATA-2 (NF-E lb) gene, indicating that our clones encode the human GATA-2 gene transcript. By RNA blot analysis, this gene is expressed in cultured cell lines derived from a number of different tissues. Transactivation experiments utilizing human GATA-2 eukaryotic expression vectors indicate that the GATA-2 protein interacts with the endothelin-1 GATA sequence to increase transcription of reporter genes in both BAEC and HeLa cells. These data provide the first evidence for a non-erythroid target gene regulated by GATA-2 and indicate that GATA-2 may have a more broad role in transcriptional regulation than the erythroid-specific GATA-1 protein.