OR-Z6 mRNA and β-galactosidase exhibit similar expression patterns in mouse OE. The hemisections (left nostril) shown in both columns represent a survey from anterior (top) to posterior (bottom) in the mid-to-caudal region of the OE. Left column,In situ hybridization for OR-Z6(digoxigenin-labeled riboprobe) performed in an array of 15 μm coronal cryosections of the OE from a wild-type mouse (129S3; postnatal day 24) is shown. OR-Z6⁺ neurons are restricted to endoturbinate-II and -III and ectoturbinate-3 as indicated. Similar to lacZ⁺ neurons (right column), OR-Z6⁺neurons are located at different depths of the OE; the most intensely labeled neurons are located in the apical OE. Right column, The overall distribution of OR-Z6 mRNA is almost identical to the β-galactosidase expression pattern observed in an age-matched H-lacZ6 mouse. As seen forOR-Z6 (boxed area, left column), X-gal-stained ORNs (right column) are concentrated on the tips of the central turbinates. To facilitate the comparison of the expression patterns for OR-Z6 mRNA and β-galactosidase, sections were chosen to match similar regions of the OE. Scale bar, 500 μm.