Correlating notch signaling with thymocyte maturation

The Notch receptor and its ligands are involved in many developmental proce sses. They are highly expressed in the thymus and have been implicated in t he CD4 versus CD8 lineage decision. We identified the constitutively active intracellular fragment of murine Notch-1 as capable of rendering thymomas resistant to glucocorticoid-induced apoptosis. This effect was confirmed in other T cell lines and in CD4(+)CD8(+) DP thymocytes. Activation of the No tch signaling pathway also upregulated a number of other markers that, like steroid resistance, correlate with DP maturation into both the CD4 and CD8 lineages. These results suggest that Notch signaling is critically involve d in the maturation of DP thymocytes into both CD4(+) and CD8(+) SP thymocy tes.