Fig 2: IHC confirms lack of GNAT3- and PLCß2-expressing Type II cells in Skn-1a-/- mice. A, Lingual sections from Skn-1a-/- and WT littermates were labeled with antibodies against SNAP25 (magenta) and GNAT3 (green) or PLCß2 (green). In Skn-1a-/-, there was no detectable levels of Type II cell markers GNAT3 or PLCß2. B, Semi-quantitative IHC reveals increased numbers of Type III cells in circumvallate, fungiform, and soft palate taste buds. Each dot represents a single taste bud. Box plots are summaries of all datapoints. Acquisition settings were equalized between WT and KO for all channels. Images are maximal z-projections of 12- to 16-µm image stacks. CV = circumvallate, FF = fungiform; *p < 0.05 by Kruskal–Wallis test followed by Dunn test for multiple comparisons.

Fig 3: RT-PCR confirms lack of Type II cell markers. RNA was extracted from fungiform and circumvallate taste buds of WT and Skn-1a-/- mice. After reverse transcription, cDNA was interrogated for the presence of Skn1a, Gnat3, Calhm1, and Snap25. Arrowheads denote ladder bands: Skn1a, 200 and 100 bp; Gnat3, 300 and 200 bp; Calhm1, 200 and 100 bp; Snap25, 300 and 200 bp. Data are representative of RNA extracted from three mice of each genotype; – is no template negative control, FF lanes in Skn1a and Gnat3 gel are RNA from C57bl/6j fungiform taste buds.

Fig 4: No change in the number of 5-HT3A-GFP geniculate ganglion neurons in Skn-1a-/- mice. Skn-1a-/- mice were crossed to 5-HT3A-GFP mice. A, B, Geniculate ganglia of Skn-1a-/-/5-HT3A-GFP and WT littermates (still expressing 5-HT3A-GFP) were labeled with antibodies against GFP (green), P2X3 (magenta), and SNAP25 (blue). The number of labeled cells was counted for each label. C, Percent of total cells showing GFP, P2X3, or SNAP25 immunoreactivity. KO of Skn-1a had no effect. D, Percent of total cells showing each combination of labels. KO of Skn-1a had no effect. Data are a summary of from three WT and four KO mice. Bar chart depicts sample mean and error bars show SEM.