Afferent induction of olfactory glomeruli requires N-cadherin.
Drosophila olfactory receptor neurons (ORNs) elaborate a precise internal representation of the external olfactory world in the antennal lobe (AL), a structure analagous to the vertebrate olfactory bulb. ORNs expressing the same odorant receptor innervate common targets in a highly organized neuropilar structure inside the AL, the glomerulus. During normal development, ORNs target to specific regions of the AL and segregate into subclass-specific aggregates called protoglomeruli prior to extensive intermingling with target dendrites to form mature glomeruli. Using a panel of ORN subclass-specific markers, we demonstrate that in the adult AL, N-cadherin (N-cad) mutant ORN terminals remain segregated from dendrites of target neurons. N-cad plays a crucial role in protoglomerulus formation but is largely dispensible for targeting to the appropriate region of the AL. We propose that N-cad, a homophilic cell adhesion molecule, acts in a permissive fashion to promote subclass-specific sorting of ORN axon terminals into protoglomeruli.
Hummel
Thomas
T
Howard Hughes Medical Institute, Department of Biological Chemistry, Geffen School of Medicine, Molecular Biology Institute, Box 951662, University of California, Los Angeles, Los Angeles, CA 90095, USA.
Zipursky
S Lawrence
SL
D000818:Animals; D030801:Animals, Genetically Modified; D001921:Brain / Q000378:metabolism; D015820:Cadherins / Q000235:genetics / Q000502:physiology*; D003712:Dendrites / Q000502:physiology; D004330:Drosophila; D051959:ELAV Proteins; D005455:Fluorescent Antibody Technique / Q000379:methods; D018507:Gene Expression Regulation, Developmental; D005821:Genetic Techniques / Q000401:mortality; D049452:Green Fluorescent Proteins; D008164:Luminescent Proteins / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism; D009154:Mutation; D009830:Olfactory Bulb / Q000166:cytology*; D009833:Olfactory Pathways / Q000166:cytology / Q000502:physiology; D018034:Olfactory Receptor Neurons / Q000502:physiology*; D017729:Presynaptic Terminals / Q000502:physiology*; D050683:R-SNARE Proteins; D012261:Ribonucleoproteins / Q000378:metabolism
D015820:Cadherins; D051959:ELAV Proteins; D008164:Luminescent Proteins; D008565:Membrane Proteins; D050683:R-SNARE Proteins; D012261:Ribonucleoproteins; D049452:Green Fluorescent Proteins