NEUROBLAST SPECIFICATION AND FORMATION REGULATED BY WINGLESS IN THE DROSOPHILA CNS

The Drosophila central nervous system (CNS) develops from a heterogene ous population of neural stem cells (neuroblasts), yet the genes regul ating neuroblast determination remain unknown. The segmentation gene w ingless is regionally expressed in the neuroectoderm from which neurob lasts develop. A conditional wingless mutation is used to inactivate C NS function without affecting segmentation. The stripe of wingless-exp ressing neuroectoderm generates apparently normal neuroblasts after wi ngless inactivation; however, adjacent anterior and posterior neuroect oderm requires wingless nonautonomously for subsequent neuroblast dete rmination and formation. Loss of wingless results in the absence or du plication of identified neuroblasts, highlighting its role in generati ng neuroblast diversity in the CNS.