Human transcription factor GATA-2. Evidence for regulation of preproendothelin-1 gene expression in endothelial cells

Abstract

Previously, we showed that the promoter of the gene encoding preproendothelin-1 (PPET-1) contains a GATA motif that is essential for activity and interacts with a nuclear factor similar in size and binding specificity to the erythroid transcription factor GATA-1. To identify this endothelial GATA-binding protein, a human endothelial cell cDNA library was screened with oligonucleotide probes for a portion of the zinc finger domain of GATA-1. A 2.6-kilobase cDNA encoding a 470 amino acid protein was obtained. Sequence analysis revealed a predicted protein which is the human counterpart of a related chicken protein, designated GATA-2. Human GATA-2 is expressed by a variety of cells, including erythroid, HeLa, and endothelial cells. A complex of a GATA-containing probe and recombinant GATA-2 expressed in COS cells comigrates with that present in gel shift experiments with nuclear extract derived from endothelial cells. In addition, expressed human GATA-2 protein transactivates reporter gene constructs containing either minimal GATA promoter elements or the native PPET-1 promoter in a cotransfection assay. Retinoic acid treatment of endothelial cells results in down-regulation of GATA-2 expression as well as down-regulation of PPET-1 gene expression. Human homologs of other known GATA-binding transcription factors are either absent from endothelial cells (in the case of GATA-1) or made in small quantities and not significantly affected by retinoid acid in these cells (in the case of GATA-3), making it unlikely that they regulate the PPET-1 gene. We propose that GATA-2 is the GATA-binding protein required for PPET-1 gene expression in endothelial cells.