Fig. 3. Axonal projections of P2-, M72-, MOR23- and V1rb2-expressing Ac3^-/- sensory neurons. (A-K) Whole-mount views of X-Gal-stained (blue) OSNs (except for H and I, in which the green color reflects the expression of GFP). (A,B) No glomerulus is observed in B. Inserts show the tip of the largest right turbinates of wild-type and Ac3^-/- mice. The number of P2-expressing OSNs is reduced in mutant animals. (C,D) Lateral view of P15 M72-lacZ control and Ac3^-/- animals. Closed arrows indicate the position of the wild-type medial glomeruli. The open arrow indicates the position of the novel, rostromedial glomerulus. Analysis of turbinates (inserts) shows no differences in the number of M72-expressing neurons. (E) The two medial glomeruli persist in Ac3^-/- M72-lacZ P50 mice. (F,G) Dorsal views of P15 M72-lacZ (F) control, and (G) Ac3^-/- left bulbs. Open and closed arrows indicate the topographical position of mutant and wild-type M72 glomeruli, respectively. (H,I) Medial views of right bulbs of P15 animals, in which all axonal projections corresponding to MOR23-expressing OSNs are GFP fluorescent. A novel glomerulus is formed on the rostroventral side of the bulb in Ac3 mutant animals (open arrow). (J,K) Dorsal views of the accessory olfactory bulb of V1rb2-lacZ control (J) and Ac3-null (K) 3-week-old animals. External boundaries of the left accessory olfactory bulb are shown as a dotted line in J. No obvious alteration of the typical V1rb2 map was observed. Scale bar: 1 mm. C, caudal; D, dorsal; L, lateral; M, medial; R, rostral; V, ventral.