(A, B) Both WT and KO OE contain Tuj1(+) neurons and K18(+) Sus cells. K18 also marks Bowman’s ducts/glands. In the WT these cells extend into the lamina propria as mature glands (white arrows). In the KO, K18(+) cells are frequently bunched above the basal lamina (black arrows). (C, D) Sox9, another marker of duct/gland cells, is expressed in normal glands in the lamina propriat of the WT mucosa. In the KO, piles of Sox9(+) cells accumulate above the basal lamina in the epithelium proper. (E, F) Neurons in WT and KO OE are roughly equivalent in the proportion of immature OSNs (GAP43[+] and basally situated) vs. mature OSNs (OMP[+] and apically placed). (G, H) Sox2 is expressed in Sus cells of WT and KO OE. In the basal cell compartment, fewer Sox2(+) cells can be seen in the KO than in the WT. (I, J) Fewer Hes1(+) cells are present in the basal OE of p63 KO OE. (K, L) Ascl1(+) cells are equally abundant in WT and KO OE. Type IV collagen marks the basal lamina in (C, D, G-L). Scale bars: 50 μm, and 10 μm for insets.