Developmental origin of wiring specificity in the olfactory system of Drosophila.
In both insects and mammals, olfactory receptor neurons (ORNs) expressing specific olfactory receptors converge their axons onto specific glomeruli, creating a spatial map in the brain. We have previously shown that second order projection neurons (PNs) in Drosophila are prespecified by lineage and birth order to send their dendrites to one of approximately 50 glomeruli in the antennal lobe. How can a given class of ORN axons match up with a given class of PN dendrites? Here, we examine the cellular and developmental events that lead to this wiring specificity. We find that, before ORN axon arrival, PN dendrites have already created a prototypic map that resembles the adult glomerular map, by virtue of their selective dendritic localization. Positional cues that create this prototypic dendritic map do not appear to be either from the residual larval olfactory system or from glial processes within the antennal lobe. We propose instead that this prototypic map might originate from both patterning information external to the developing antennal lobe and interactions among PN dendrites.
Jefferis
Gregory S X E
GS
Department of Biological Sciences, Stanford University, Stanford, CA 94305, USA.
Vyas
Raj M
RM
Berdnik
Daniela
D
Ramaekers
Ariane
A
Stocker
Reinhard F
RF
Tanaka
Nobuaki K
NK
Ito
Kei
K
Luo
Liqun
L
D000818:Animals; D001369:Axons / Q000502:physiology / Q000648:ultrastructure; D002454:Cell Differentiation; D003712:Dendrites / Q000502:physiology / Q000648:ultrastructure; D004331:Drosophila melanogaster / Q000196:embryology* / Q000254:growth & development; D004625:Embryo, Nonmammalian / Q000166:cytology / Q000502:physiology; D007814:Larva; D009024:Morphogenesis; D018034:Olfactory Receptor Neurons / Q000166:cytology / Q000502:physiology*; D017729:Presynaptic Terminals / Q000502:physiology / Q000648:ultrastructure; D012903:Smell / Q000502:physiology*