Semaphorin - Neuropilin repulsive signaling works synergistically with the forward EphB signaling to guide neural crest cells down the rostral half of somites in mice ; in chick embryos , semaphorin acts in the cephalic region to guide neural crest cells through the pharyngeal arches .
Semaphorin - neuropilin repulsive signaling works synergistically with EphB signaling to guide neural crest cells down the rostral half of somites in mice . 
 In chick embryos , semaphorin acts in the cephalic region to guide neural crest cells through the pharyngeal arches .