Title:
Molecular and cellular mechanism underlying neural map formation in Drosophila

Takahiro Chihara
Department of Genetics, Graduate School of Pharmaceutical Sciences, The University of Tokyo

Abstract:
The function of nervous systems depends on the development of specific synaptic connections between trillions of neurons; these connections lead to the formation of a neural map, which is the key feature of brain organization. Selection of synaptic partners involves the interaction of presynaptic axons and postsynaptic dendrites, however, the molecular mechanism underlying the synaptic matching between axon and dendrites during neural map formation remains unclear. Here we use the Drosophila olfactory system, which provides a unique opportunity to study neural map formation in a single cell resolution in vivo. Olfactory receptor neurons (ORNs) expressing the same odorant receptors converge their axonal projections to specific glomerular targets in the antennal lobe, thereby creating an odor map in this first olfactory structure of the central nervous system. Antennal lobe projection neurons (PNs) send dendrites to glomeruli and synapse with the ORN axons; the PN axons then relay the olfactory information to higher brain centers. From genetic mosaic screen [1], we identified key molecules, Meigo (UPR-related ER protein)[2], Strip (negative regulator of Hippo)[3] and Eph/ephrin (axon guidance molecules), which cell autonomously and/or non-autonomously act in neural map formation. I will present our attempts to understand the molecular mechanism of both axonal and dendritic targeting and to elucidate the in vivo cellular interactions and interdependence between them for the self-organization of stereotyped neural map in the brain.

References
[1] Chihara, T. et al. Nat Neurosci 10: 828-37 (2007)
[2] Sekine, SU et al. Nat Neurosci 16: 683-91 (2013)
[3] Sakuma, C. et al. Nat Commun 5: 5180 (2014)