Like all blood cells, T Lymphocytes are derived from hematopo ietic stem cells (HSC) and their differentiation depends on the intergration of multiple transcriptional depends on the intergration of multiple transcriptional regulator, like Notchh signaling and GATA-3, whose expression levels are critical for specification and commitment into T cells. Therefore we want to examine the exact role of GATA-3 during T cell commitment and differentiation and investigate the interplay between Notch signaling and GATA-3.