Developmental Programs Regulating the Fate Specification, Identity and Function of Dorsal Fan-Shaped Body Neurons in Drosophila melanogaster Central Complex

Behaviors like sleep and foraging depend on diverse neural circuits, shaped by spatiotemporal gene expression during development. This dissertation explores how hormonal signaling and transcription factor E93 regulate neurodevelopment in Drosophila to generate dorsal fan-shaped body (dFB) neurons critical for sleep and metabolism. Chapter 1 shows 23E10 dFB neurons arise from type II neural stem cells (NSCs) DL1/DM1, requiring ecdysone signaling and E93 for specification. Disrupting ecdysone signaling, or E93, in type II NSCs causes neuronal defects and sleep deficits, establishing E93 as a temporal determinant linking hormonal cues to sleep circuit maturation. Chapter 2 focuses on 84C10 dFB neurons that regulate metabolism, derived from DL1/DM4 type II NSCs and requiring E93 for specification. E93 is expressed post-mitotically in these neurons; its loss disrupts dFB innervation, eliminates sugar preference, and suppresses diet-induced triglyceride accumulation. Overall, this dissertation highlights E93’s essential role in specifying dFB neurons that regulate sleep and metabolism.