T-cell expression of the human GATA-3 gene is regulated by a non-lineage-specific silencer

The GATA-3 transcription factor is required for development of the T-cell l ineage and Th2 cytokine gene expression in CD4 T-cells, We have mapped the DNase-I-hypersensitive (HS) regions of the human GATA-3 gene in T-cells and non-T-cells and studied their transcriptional activities. HS I-III, locate d 5' from the transcriptional initiation site, were found in hematopoietic and non-hematopoietic cells, whereas HS IV-VII, located 3' from the transcr iptional start site, were exclusively observed in T-cells, Among these hype rsensitive sites, two transcriptional control elements were found, one in t he first intron of the GATA-3 gene and the other between 8.3 and 5.9 kiloba ses 5' from the GATA-3 transcriptional initiation site. The first intron ac ted as a strong transcriptional activator in a position-dependent manner an d with no cell-type specificity, The upstream regulatory element could conf er T-cell specificity to the GATA-3 promoter activity, and analysis of this region revealed a 707-base pair silencer that drastically inhibited GATA-3 promoter activity in non-T-cells. Two CAG-GTG; E-boxes, located at the 5'- and 3'-ends of the silencer, were necessary for this silencer activity. Th e 3'-CAGGTG E-box could bind USF proteins, the ubiquitous repressor ZEE, or the basic helix-loop-helix proteins E2A and HEB, and we showed that a comp etition between ZEE and EBA/HEB proteins is involved in the silencer activi ty.