Transmembrane grasshopper Semaphorin I promotes axon outgrowth in vivo.
Members of the Semaphorin family of glycoproteins play an important role in axonal pathfinding by functioning as inhibitory guidance cues. Here we provide evidence that a transmembrane form of Semaphorin (Semaphorin I), which is expressed by bands of epithelial cells in the developing grasshopper limb bud, functions as an attractive/permissive cue for the growth cones of the subgenual organ. In addition, we demonstrate that Semaphorin I is needed for initial axonal outgrowth from the subgenual organ. These results are consistent with an alternative function for a transmembrane form of Semaphorin and may explain the previously reported arrest of the proximal extension of the subgenual organ growth cones in the absence of the Ti1 pioneer pathway.
Wong
J T
JT
Department of Anatomy, University of British Columbia, Vancouver, Canada.
Yu
W T
WT
O'Connor
T P
TP
D000818:Animals; D000911:Antibodies, Monoclonal; D001369:Axons / Q000502:physiology*; D015816:Cell Adhesion Molecules, Neuronal / Q000096:biosynthesis / Q000276:immunology / Q000502:physiology*; D004847:Epithelial Cells / Q000378:metabolism; D006110:Grasshoppers / Q000196:embryology* / Q000378:metabolism; D006358:Hot Temperature; D018878:Limb Buds / Q000294:innervation / Q000378:metabolism* / Q000502:physiology; D009474:Neurons / Q000502:physiology; D039961:Semaphorins
D000911:Antibodies, Monoclonal; D015816:Cell Adhesion Molecules, Neuronal; D039961:Semaphorins