Fig. 4. Immunofluorescence of basal and epithelial markers. Hoxb13 homozygous mutant luminal cells display loss of polarity. (A,B) Hoxb13 expression and localization was determined by using an antibody to the ß-galactosidase reporter. (C,D) Androgen Receptor (AR) expression is intact in homozygous mutant epithelium. Basal cell marker CD44 is mis-expressed on apical surface of mutant epithelium (B,D yellow arrowheads). The tall-columnar morphology of heterozygous luminal cells (A,C) is evident when compared to the simple-cuboidal morphology of homozygous mutant luminal cells (B,D). St, stroma; Lu, lumen. Scale bar: 10 µm.