The GATA3 Leeporter™ Luciferase Reporter cell line is a stably transfected HEK 293 cell line which expresses Renilla luciferase reporter gene under the transcriptional control of the GATA3 response element, so that the cell line is designed to measure the transcriptional activity of GATA3. As a zinc-finger transcription factor, GATA3 (GATA-binding protein 3) plays a critical role in early and late T cell differentiation, which regulates Th1/Th2 differentiation. GATA3 has been shown to induce Th2 differentiation and repress Th1 differentiation. GATA3 is also known to promote the secretion of IL-4, IL-5 and IL-13 from Th2 cells. The GATA3 induction by phorbol 12-myristate 13-acetate (PMA)  is shown in Figure 1.