Development Of Peripheral Taste Neural Pathways

Taste information is received by taste buds and transmitted to the hindbrain by special visceral sensory nerves,the taste nerves.The integrity of taste nerves is essential for the maintenance of taste buds in adult animals.However,a role for taste nerves in the ontogeny of taste buds,in the embryo and at early postnatal stages,has been controversial and is still unresolved.In this study,I establish in a definitive manner that embryonic taste bud formation is nerve-dependent in mouse,thus unifying mechanistically the maintenance/regeneration and ontogeny of these organs.Parallel to this work,I re-examined the possibility(previously excluded by other authors)of a role for the transcription factor Foxgl in epibranchial ganglion formation.I find that Foxgl is essential for the differentiation of gustatory neurons in the geniculate ganglion.This novel role,together with previously described ones in the olfactory epithelium,otic placode and retina,unveils a striking physiological coherence of the functions of Foxgl(outside its well established one in the cortex),as a master transcription factor for neurons involved in "special senses":vision,hearing,smell and taste.