Olfactory sensory axons expressing a dominant-negative semaphorin receptor enter the CNS early and overshoot their target.
Sensory axons extend from the chick olfactory epithelium to the telencephalon well before the maturation of their target, the olfactory bulb. During a waiting period of several days, olfactory axons arrive and accumulate outside the CNS while the bulb differentiates beneath them. Semephorin-3A is expressed in the tel-encephalon during this period and has been proposed to prevent their entry into the CNS. We show that the misexpression of a dominant-negative neuropilin-1 that blocks SEMA-3A-mediated signaling in olfactory sensory axons induces many of them to enter the tel-encephalon prematurely and to overshoot the olfactory bulb. These results suggest that chemorepellents can prevent the premature innervation of immature targets.
Renzi
M J
MJ
Department of Neuroscience, University of Pennsylvania School of Medicine, Philadelphia 19104, USA.
Wexler
T L
TL
Raper
J A
JA
D000818:Animals; D001369:Axons / Q000378:metabolism* / Q000648:ultrastructure; D002490:Central Nervous System / Q000166:cytology / Q000196:embryology; D002642:Chick Embryo; D018274:Electroporation; D005799:Genes, Dominant; D036341:Intercellular Signaling Peptides and Proteins; D009419:Nerve Tissue Proteins / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism*; D009475:Neurons, Afferent / Q000166:cytology / Q000378:metabolism*; D039942:Neuropilin-1; D009832:Olfactory Nerve / Q000196:embryology* / Q000378:metabolism; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000235:genetics; D040121:Semaphorin-3A; D013687:Telencephalon / Q000196:embryology; D014162:Transfection
D036341:Intercellular Signaling Peptides and Proteins; D009419:Nerve Tissue Proteins; D011994:Recombinant Proteins; D040121:Semaphorin-3A; C095114:collapsin response mediator protein-2; D039942:Neuropilin-1