EXPRESSION PATTERNS OF JAGGED, DELTA1, NOTCH1, NOTCH2, AND NOTCH3 GENES IDENTIFY LIGAND-RECEPTOR PAIRS THAT MAY FUNCTION IN NEURAL DEVELOPMENT

Notch genes encode receptors for a signaling pathway that regulates ne urogenesis. The DSL (Delta/Serrate/lag-2) genes encode ligands that bi nd and activate Notch. In situ hybridization was used to determine the spatiotemporal expression of Notch1, Notch2, and Notch3, and the DSL ligands, Jagged and Delta1, in an effort to identify potential ligand- receptor pairs that function during development of the rat nervous sys tem. Here we describe both distinct and overlapping expression pattern s for these genes in neural progenitors that form both the central and the peripheral nervous systems. The punctate expression patterns we d etected for Jagged and Delta1 are consistent with their role in mediat ing lateral inhibition, a process proposed to regulate neural determin ation. Furthermore, within the ventricular zone of the neural tube and retina, Jagged and Delta1 were expressed in complementary regions, su ggesting that different DSL-Notch combinations may direct the developm ent of distinct neural subtypes.