The Pierchala lab has evaluated neurotrophic factor receptor complexes in the development of peripheral sensory neurons, with a focus on mechanoreceptors and chemoreceptors. The lab's analysis of Ret (GDNF receptor) mutant mice revealed that Ret, along with GDNF, are critical for embryonic cell fate specification of oral sensory geniculate ganglion neurons that innervate taste buds. In adulthood, Ret expression is restricted to a subset of geniculate ganglion neurons which respond specifically to mechanical stimulation of the tongue surface. Further investigation of these tactile neurons revealed that their terminals lie outside of the taste bud, but still in fungiform papillae. These axons have a perigemmal projection outside of the taste bud and terminate in the anterior lingual epithelium. Using molecular genetic strategies, they have identified additional growth factors, as well as transcription factors, that are critical for cell fate specification of these oral sensory neurons, and area of active research.