ACTIVATION OF THE ERYTHROPOIETIN RECEPTOR PROMOTER BY TRANSCRIPTION FACTOR GATA-1

Erythropoietin, a glycoprotein produced by the kidneys in response to anemia and hypoxia, is a major growth factor for cells of the erythroid lineage. Erythropoietin interacts with high-affinity cell surface receptors (EpoR) present on developing progenitors and is required for their survival. Previously we characterized the gene for EpoR and demonstrated that its promoter acts in a cell-specific manner. Here we show that the hematopoietic-specific transcription factor GATA-1 is necessary, and indeed is sufficient as the sole cell-restricted regulator, for activation of the EpoR promoter in fibroblast transfection assays. Hence, GATA-1, which participates in transcriptional control of the majority of erythroid-expressed genes, also acts on the promoter of an essential lineage-restricted receptor (EpoR). This central contribution of GATA-1 to EpoR promoter function provides a mechanism whereby a cell-restricted regulator may ensure the viability and subsequent maturation of progenitor cells during hematopoietic differentiation.