Temporal target restriction of olfactory receptor neurons by Semaphorin-1a/PlexinA-mediated axon-axon interactions.
Axon-axon interactions have been implicated in neural circuit assembly, but the underlying mechanisms are poorly understood. Here, we show that in the Drosophila antennal lobe, early-arriving axons of olfactory receptor neurons (ORNs) from the antenna are required for the proper targeting of late-arriving ORN axons from the maxillary palp (MP). Semaphorin-1a is required for targeting of all MP but only half of the antennal ORN classes examined. Sema-1a acts nonautonomously to control ORN axon-axon interactions, in contrast to its cell-autonomous function in olfactory projection neurons. Phenotypic and genetic interaction analyses implicate PlexinA as the Sema-1a receptor in ORN targeting. Sema-1a on antennal ORN axons is required for correct targeting of MP axons within the antennal lobe, while interactions amongst MP axons facilitate their entry into the antennal lobe. We propose that Sema-1a/PlexinA-mediated repulsion provides a mechanism by which early-arriving ORN axons constrain the target choices of late-arriving axons.
Sweeney
Lora B
LB
Howard Hughes Medical Institute, Department of Biological Sciences and Neurosciences Program, Stanford University, Stanford, CA 94305, USA.
Couto
Africa
A
Chou
Ya-Hui
YH
Berdnik
Daniela
D
Dickson
Barry J
BJ
Luo
Liqun
L
Komiyama
Takaki
T
D000818:Animals; D001369:Axons / Q000502:physiology*; D004330:Drosophila / Q000502:physiology*; D029721:Drosophila Proteins / Q000235:genetics / Q000502:physiology*; D005821:Genetic Techniques; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000502:physiology*; D009434:Neural Pathways / Q000502:physiology; D018034:Olfactory Receptor Neurons / Q000502:physiology*; D010641:Phenotype; D011956:Receptors, Cell Surface / Q000235:genetics / Q000502:physiology*; D039961:Semaphorins / Q000235:genetics / Q000502:physiology*; D012679:Sense Organs / Q000294:innervation
D029721:Drosophila Proteins; D009419:Nerve Tissue Proteins; D011956:Receptors, Cell Surface; D039961:Semaphorins; C116483:plexA protein, Drosophila; C477531:semaphorin 1a, Drosophila