Figure 4. Representative sections of the middle ear and Eustachian tube mucosae of Chd7 ^+/+ and Chd7^Ome/+ littermates.

Few goblet cells could be found in the middle ear (A) and Eustachian tube mucosae (C) of Chd7^+/+ littermate mice. By contrast, goblet cells were present at high density among other cells in the epithelium of the middle ear cavity (B) and the duct of the Eustachian tube (D) of Chd7^Ome/+ mice (typical goblet cells are indicated by arrows). Goblet cells have a distinctly polarized morphology in which the nucleus stains black in color at the cell base, and the mucus stains a deep rose color in the middle and apical portions of the cell. Scale bars  = 50 μm.