Fig. 6. O/E2^lacZ/+/O/E3^GFP/+ double heterozygous animals exhibit similar projection defects independent of Tau overexpression. (A) The ORN projection patterns on dorsal OB of adult O/E2^lacZ/+ and O/E3^GFP/+ mice were visualized by whole-mount X-gal staining. ORN axons and glomeruli are visible on the entire dorsal surface of the OB. (B) X-gal staining pattern of an O/E2^lacZ/+/O/E3^GFP/+ animal show areas where ORN axons and glomeruli are absent. (C) X-gal staining pattern of an O/E3^GFP/+ animal carrying two OMP-tau-lacZ alleles reveals a normal projection pattern, indicating that the extra gene dose of tau-ß-galactosidase from the OMP-taulacZ alleles does not cause a projection defect. (D) Coronal sections of the OB from an animal with the same genotype as the one described in C show normal projections to the dorsal surface. (E) Coronal sections of the OB from an O/E3^GFP/GFP animal carrying one OMP-tau-lacZ allele show the same projection defect seen in O/E3^GFP/GFP homozygous animals.