Semaphorin-1a controls receptor neuron-specific axonal convergence in the primary olfactory center of Drosophila.
In the olfactory system of Drosophila, 50 functional classes of sensory receptor neurons (ORNs) project in a highly organized fashion into the CNS, where they sort out from one another and converge into distinct synaptic glomeruli. We identified the transmembrane molecule Semaphorin-1a (Sema-1a) as an essential component to ensure glomerulus-specific axon segregation. Removal of sema-1a in ORNs does not affect the pathfinding toward their target area but disrupts local axonal convergence into a single glomerulus, resulting in two distinct targeting phenotypes: axons either intermingle with adjacent ORN classes or segregate according to their odorant receptor identity into ectopic sites. Differential Sema-1a expression can be detected among neighboring glomeruli, and mosaic analyses show that sema-1a functions nonautonomously in ORN axon sorting. These findings provide insights into the mechanism by which afferent interactions lead to synaptic specificity in the olfactory system.
Lattemann
Marc
M
Institut für Neurobiologie, Universität Münster, Badestrasse 9, D-48149 Münster, Germany.
Zierau
Ariane
A
Schulte
Claus
C
Seidl
Sascha
S
Kuhlmann
Britta
B
Hummel
Thomas
T
D000818:Animals; D001369:Axons / Q000502:physiology*; D003712:Dendrites / Q000502:physiology; D004330:Drosophila / Q000502:physiology*; D009154:Mutation; D009833:Olfactory Pathways / Q000254:growth & development / Q000502:physiology*; D018034:Olfactory Receptor Neurons / Q000502:physiology*; D039961:Semaphorins / Q000235:genetics / Q000502:physiology*; D012679:Sense Organs / Q000294:innervation; D015398:Signal Transduction / Q000502:physiology
D039961:Semaphorins; C477531:semaphorin 1a, Drosophila