Figure 3.

Human TAS2R mRNA is present in a subset of α-gustducin-expressing cells. Dual-color in situ hybridization was done using a digoxigenin-labeled antisense riboprobe specific for human α-gustducin and a fluorescein-labeled antisense riboprobe specific for hTAS2R14. For the detection of hybridization signals, an anti-digoxigenin antibody coupled to horseradish peroxidase was used in combination with fluorescein–tyramide solution, resulting in a green fluorescent color precipitate specific for α-gustducin (A). The fluorescein-labeled hTAS2R14 probe was detected with an anti-fluorescein antibody coupled to alkaline phosphatase in combination with fast red solution, leading to a red fluorescent color precipitate specific for hTAS2R14 (B). C, Overlay of A and B. D same as C superimposed on a topographical black and white image of the scanned specimen. Pictures were taken by confocal laser scanning microscopy (Leica TCS SP2) of the entire depth of the tissue. The resulting z-stack was flattened using the averaging function of the Leica confocal software. Cells expressing α-gustducin and hTAS2R14 are labeled with arrows (C). Scale bar, 40 μm.