Mechanisms underlying olfactory neuronal connectivity in Drosophila - The atonal lineage organizes the periphery while sensory neurons and glia pattern the olfactory lobe

Patterning of the antennal lobe of adult Drosophila occurs through a comple x interaction between sensory neurons, gla, and central neurons of larval a nd adult origin. Neurons from the olfactory sense organs are organized into distinct fascicles lined by glial cells. The glia originate from one of th e three types of sensory lineages-specified by the proneural gene atonal. G ain-of-function as well as loss-of-function analysis validates a role for c ells of the Atonal lineage in the ordered fasciculation of sensory neurons. Upon entry of the antennal nerve to central regions, sensory neurons at fi rst remain closely associated with central glia which lie around the periph ery of the lobe anlage. Coincident with the arrival of sensory neurons into the brain, glial precursors undergo mitosis and neural precursors expressi ng Dachshund appear around the lobe. Sensory neurons and glial cells projec t into the lobe at around the same time and are likely to coordinate the co rrect localization of different glomeruli. The influence of sensory neurons on the development of the olfactory lobe could serve to match and lock per ipheral and central properties important for the generation of olfactory be havior. (C) 2000 Academic Press.