Fig. 3.

In situ hybridization (ISH) for Hoxb13 expression (A–I) and immunohistochemistry (IHC) for Hoxb13 protein localization (J–L) in the developing rat prostate. For ISH, sections from d 10 and 30 intact prostates were processed together to allow direct comparisons of signal strength. For IHC, intact prostate sections from d 6, 10, and 30 were processed together to allow direct comparisons of stain intensity. At d 10, Hoxb13 mRNA signal was similar among the (A) VP, (B) LP, and (C) DP lobes. By d 30, a distinct expression gradient was observed with (D) highest expression in the VP, (E) moderate expression in the LP, and (F) lowest expression levels in the DP. This gradient is best observed at (G and H) lower power of a whole prostatic complex on a single slide where the adjacent lobes can be directly compared. A longitudinal gradient along the ductal length was also apparent with intense Hoxb13 expression in the distal regions of all lobes and low signal intensity in the proximal ducts (I). IHC staining of Hoxb13 protein in the VP on d (J) 6, (K) 10, and (L) 30 revealed low protein staining in epithelial nuclei and strong Hoxb13 protein levels by d 30 (E, epithelial ducts; scale bar, 50 μm).