Pre-target axon sorting establishes the neural map topography.
Sensory information detected by the peripheral nervous system is represented as a topographic map in the brain. It has long been thought that the topography of the map is determined by graded positional cues that are expressed by the target. Here, we analyzed the pre-target axon sorting for olfactory map formation in mice. In olfactory sensory neurons, an axon guidance receptor, Neuropilin-1, and its repulsive ligand, Semaphorin-3A, are expressed in a complementary manner. We found that expression levels of Neuropilin-1 determined both pre-target sorting and projection sites of axons. Olfactory sensory neuron-specific knockout of Semaphorin-3A perturbed axon sorting and altered the olfactory map topography. Thus, pre-target axon sorting plays an important role in establishing the topographic order based on the relative levels of guidance molecules expressed by axons.
Imai
Takeshi
T
Department of Biophysics and Biochemistry, Graduate School of Science, University of Tokyo, Tokyo 113-0032, Japan.
Yamazaki
Takahiro
T
Kobayakawa
Reiko
R
Kobayakawa
Ko
K
Abe
Takaya
T
Suzuki
Misao
M
Sakano
Hitoshi
H
D000818:Animals; D001369:Axons / Q000502:physiology*; D001931:Brain Mapping; D002450:Cell Communication; D003463:Cues; D000242:Cyclic AMP / Q000378:metabolism; D008024:Ligands; D051379:Mice; D018345:Mice, Knockout; D008822:Mice, Transgenic; D009457:Neuroglia / Q000502:physiology; D039942:Neuropilin-1 / Q000378:metabolism*; D009830:Olfactory Bulb / Q000166:cytology / Q000502:physiology*; D009831:Olfactory Mucosa / Q000166:cytology / Q000502:physiology; D009833:Olfactory Pathways / Q000166:cytology / Q000502:physiology*; D018034:Olfactory Receptor Neurons / Q000166:cytology / Q000502:physiology*; D018035:Receptors, Odorant / Q000378:metabolism; D040121:Semaphorin-3A / Q000378:metabolism; D015398:Signal Transduction
D008024:Ligands; D018035:Receptors, Odorant; C488217:Sema3a protein, mouse; D040121:Semaphorin-3A; D039942:Neuropilin-1; D000242:Cyclic AMP