Interactions between GATA transcription factors and the DNaseI hypersensitive sites in the human β-globin gene LCR

In this study, we analyze the binding of nuclear proteins isolated from the hydroxyurea (Hu)-induced and uninduced HEL cells to the DNasel hypersensitive sites III (HS3 -14991-14716 bp) and IV(HS4 -18586--18306 bp) in the human beta -globin gene locus control region (LCR). Using Western blot assay, we demonstrate that GATA-1 transcription factor in HEL cells is increased following the induction of Hu, while GATA-2 transcription factor is decreased. Based on both the competition EMSA and the Western blot assay, our data reveal that the nuclear protein isolated from the uninduced HEL cells, which can bind to the HS3 and HS4 core DNA sequences, is mainly GATA-2; however, the nuclear proteins isolated from the Hu-induced HEL cells, which can bind to the HS3 and HS4 core DNA sequences, are mainly GATA-1 and GATA-X (a kind of unknown GATA factor). These results suggest that the erythroid specific transcription factors (GATA-1 and GATA-2) in the Hu-induced and uninduced HEL cells can selectively bind to the HS3 and HS4 core DNA sequences in the human beta -globin gene LCR, indicating that GATA factors (GATA-1 and GATA-2) may play very important role in the regulation of the beta -globin gene expression.