Figure 2. Conditional deletion of Lhx2 in immature OSNs decreases the abundance of most OR mRNAs. A, In 123Cre:Z/EG mice, recombination-dependent GFP expression marks OSNs in the immature and mature OSN layers of the olfactory epithelium. Dashed line, location of the basal lamina separating the olfactory epithelium and lamina propria. Scale bar, 20 µm. B–E, Gap43 immunoreactivity (B, D) and in situ hybridization for Gap43 mRNA (C, E) identify immature OSN cell bodies in 123Cre:Lhx2fl/fl mice (D, E) and littermate controls (B, C). F–I, Omp immunoreactivity (F, H) and in situ hybridization for Omp mRNA (G, I) identify mature OSN cell bodies in 123Cre:Lhx2fl/fl mice (H, I) and littermate controls (F, G). Scale bars, 20 µm. J, In 123Cre:Lhx2fl/fl mice, the abundance of 676 OR mRNAs decreases (p < 0.01; n = 4; FDR <1%). •, Significant decrease; +, no difference from littermate controls. K, The percentage of class I ORs affected by Lhx2 deletion in immature OSNs is very similar to the percentage of Class II ORs affected, and the magnitude of the decreases are similar for both classes of ORs. Error bars represent SDs.