Figure 2

TrkA-like immunoreactivity does not co-localize with TrkA expression in the olfactory epithelium.

(a) RT-PCR shows TrkA expression (upper panel) in brain (Br), but not in olfactory epithelium (OE) nor olfactory bulb (OB), heart (Hr) and eye, all from adult animals. Beta actin signals (lower panel) are of similar intensity for all tissues. Arrowhead, position of amplification product from genomic DNA. (b) Left side, Western Blot with protein extracts from brain (Br) and olfactory epthelium (OE). Apparent molecular weight for several bands (asterisks) in brain and olfactory epithelium was determined from line scans (right side), only brain extracts show expected band (arrowhead). (c–f) Whole mounts of 5 dpf zebrafish larvae; (g–j), 8–10 μm sections from the whole mounts depicted above. Panels (c, f, g, j) show TrkA antibody staining, panels (d, e, h, i) depict in situ hybridization with TrkA probe. (c) TrkA antibody staining labels several structures in the inner ear of zebrafish larvae (asterisks). (d) TrkA probe labels similar structures in the inner ear (asterisks). (e) No signal is observed with the same TrkA probe in the olfactory epithelium of the same larvae. (f) However, TrkA antibody clearly labels several cells in the olfactory epithelium. (g) Specific labeling (barbed line) in hair cells of the macula (yellow due to complete overlap with HCS1 staining (red), a hair cell marker⁵¹. Blue, DAPI as nuclear counterstain. (h) The TrkA probe labels hair cells of the macula (barbed line). (i) No signal from TrkA probe detected in sections of the olfactory epithelium. (j) In contrast, TrkA antibody labels sparse cells in the OE with a globose morphology. Scale bars 20 μm for (g–j).