Regulation of IL-4 gene expression by distal regulatory elements and GATA-3 at the chromatin level

Using a transgenic approach, we examined distal regulatory elements located in the 1L-4 locus and the role of GATA-3 at these elements. The intergenic DNase I hypersensitive sites (HSS) showed strong enhancement, and the intr onic enhancer (IE) and HS5/HS5a sites showed weaker enhancement of the IL-4 promoter. Elements in the 3' region of the IL-4 gene contributed to Th2 sp ecificity. All individual enhancers were T cell activation dependent but no t Th2 specific, with the exception of IE. However, when these distal elemen ts were combined into a "minilocus," expression was strongly enhanced and T h2 specific. GATA-9 mediated strong enhancement of IL-4 promoter activity i n Th1 cells when the promoter was embedded in the minilocus or linked to HS S and IE, demonstrating that GATA-3 acts through these elements to regulate IL-4 gene expression.