Jagged-mediated Notch signaling maintains proliferating neural progenitors and regulates cell diversity in the ventral spinal cord.

Previous studies have shown that Delta-mediated Notch signaling regulates the number of early differentiating neurons. However, the role of Notch activation and Jagged-mediated signaling during late neurogenesis remains poorly defined. In the developing spinal cord of zebrafish, GABAergic Kolmer-Agduhr (KA'') cells and motor neurons (MN) emerge sequentially from their progenitors in the p3 domain. Jagged2 is expressed uniformly in the pMN domain during late neurogenesis where Olig2 is required for its expression. We suggest that Jagged2 interacts ventrally with progenitors in the adjacent p3 domain, where it has a critical role in the maintenance of proliferating neural progenitors and in preventing differentiation of these progenitors as GABAergic KA'' cells or secondary MN. This study identifies a critical role for Jagged-Notch signaling in the maintenance of proliferating neural precursors in a discrete compartment of the neural tube during the continuing growth and development of the vertebrate nervous system.