Figure 2

TrkB PLCγ-site facilitates taste bud innervation during development. (A) E16.5, all neural buds (Trkb^P/P 54 ± 17.4 vs. Trkb^W/W 113.3 ± 8.3, P <0.01; Trkb^D/D 33.3 ± 5, P <0.001 vs. Trkb^W/W; P = 0.119 vs. Trkb^P/P); Tip (Trkb^P/P 35.3 ± 18.6 vs. Trkb^W/W 85.3 ± 5.8, P <0.01; Trkb^D/D 31.3 ± 4.2, P <0.001 vs. Trkb^W/W, P = 0.734 vs. Trkb^P/P), (n = 3) all genotypes. (B) E16.5 tongue images (tip) stained with P2X3 and TUJ1 antibodies to visualize geniculate neuron afferents and all neuronal fibres, respectively, as well as neural buds. (C, E) P0, all innervated taste buds (Trkb^P/P 163.2 ± 7.8 (n = 5) vs. Trkb^W/W 122.2 ± 17.1 (n = 6), P <0.001; Trkb^D/D 38.7 ± 7.57 (n = 3), P <0.001 vs. Trkb^W/W and Trkb^P/P). Tip (Trkb^P/P (n = 5) 133.6 ± 9.2 vs. Trkb^W/W (n = 6) 101.3 ± 18.2, P <0.01; Trkb^D/D 29.3 ± 7.6 (n = 3), P <0.001 vs. Trkb^W/W and Trkb^P/P). All innervated taste buds (Trkb^S/S 56.3 ± 3.5 vs. Trkb^+/+ 142 ± 11.5, P <0.001); Tip (Trkb^S/S 52.3 ± 3.2 vs. Trkb^+/+ 117 ± 10.7, P <0.001), (n = 3) both genotypes. (D, F) P0 tongue images (tip) stained with TROMA-I and TUJ1 antibodies to visualize innervations into single taste buds. (G, H) Innervated taste buds at 3 months, all (Trkb^P/P 108.3 ± 28.5 vs. Trkb^W/W 90 ± 13.1, P = 0.368); Tip (Trkb^P/P 87 ± 23.9 vs. Trkb^W/W 73 ± 13.1, P = 0.423). All taste buds (Trkb^S/S 15 ± 1 vs. Trkb^+/+ 99.3 ± 12.7, P <0.001); Tip (Trkb^S/S 14 ± 1 vs. Trkb^+/+ 77.7 ± 11.2, P <0.001). (n = 3) all genotypes. P statistic from unpaired Student’s t-tests, mean ± s.d. Arrowheads indicate neural buds (B), and innervated taste buds (D, F) respectively. Scale bars in B, D, F, 400 μm.