GATA Transcription Factors Negatively Regulate Erythropoietin Gene Expression

We examined regulation of the human erythropoietin (Epo) gene through the GATA sequence in the Epo promoter, and demonstrated that Hep3B and HepG₂ cells express human GATA-2 (hGATA-2) mRNA and protein. Nuclear extracts of QT6 cells transfected with hGATA-1, -2 or -3 transcription factors revealed specific binding to the GATA element in the human Epo gene promoter by gel mobility shift assay. Transient transfection of Hep3B cells with hGATA-1, -2 or -3 demonstrated that each of these transcription factors significantly decreased the level of expression of Epo mRNA as assessed by a competitive polymerase chain reaction. Furthermore, transient transfection of Hep3B cells with hGATA-1, -2 and -3 and an Epo reporter gene construct showed significant inhibition of the Epo promoter. We conclude that the hGATA-1, -2 and -3 transcription factors specifically bind to the GATA element in the human Epo gene promoter and negatively regulate Epo gene expression.