Fig. 3.

Shh expressed from sensory neurons mediates long-term maintenance of TRCs. (A) Peeled epithelium from neuronal Shh knockout mice at either 8 or 12 wk of age, immunostained with K8 (red) and DAPI (blue). Note that TRCs in Avil^Cre/+;Shh^flox/flox mice are present at 8 wk but are eliminated in ∼85% of fungiform papillae at 20 wk. Fungiform papillae with partial TRC loss are denoted by yellow arrows. (Scale bars, 100 μm.) (B) Representative cryosections of fungiform papillae stained with K8 (red) and DAPI (blue). (Scale bars, 10 μm.)