Publisher Summary The semaphorin family contains a large number of phylogenetically
conserved proteins and includes several members that have been shown to function in
repulsive axon guidance. The importance of repulsive cues in path finding and target
selection has now been firmly established at the cellular and molecular levels. Semaphorin
III (Sema III) is a secreted protein that in vitro causes neuronal growth cone collapse and
chemorepulsion of neurites, and in vivo is required for correct sensory afferent innervations …