JAGGED2 - A SERRATE-LIKE GENE EXPRESSED DURING RAT EMBRYOGENESIS

DSL (Delta, Serrate, Lag-2) ligands activate Notch signaling and there by regulate the differentiation of many different cell types during de velopment. We have isolated a novel Serrate-like gene, Jagged2, whose amino acid sequence and expression pattern during rat embryogenesis su ggest that it functions as a ligand for Notch. In contrast to previous ly described DSL ligands for Notch, Jagged2 is not widely expressed in the developing central nervous system, However, Jagged2 and Notch1 ar e coexpressed in the apical ectodermal ridge (AER), suggesting a role for this ligand-receptor pair in limb development. Furthermore, unlike Jagged1, Jagged2 is coexpressed with Notch in the developing thymus, where it may induce Notch signaling to direct T-cell fate. Our data ar e consistent with the idea that the diversity of cell types regulated by Notch signaling is a consequence of activation of unique Notch isof orms by different DSL ligands. (C) 1996 Academic Press, Inc.