Expression of Fem1b in developing prostate and testis. A: Quantitative real-time RT-PCR analysis of Fem1b expression in prostate lobes and seminal vesicles from 8-week old Swiss-Webster mice. Expression levels are normalized to β-actin expression at 1 × 106 arbitrary units; error bars correspond to one standard deviation. B: Expression of Fem1b in the urogenital sinus at post-natal day 2. Abbreviations: ap, anterior prostate; bl, bladder; dd, ductus deferens. C-G: Expression of Nkx3.1 and Fem1b in adjacent sections using in situ hybridization. C, D: Expression of Nkx3.1 and Fem1b in epithelial cells of anterior prostate ducts at post-natal day 9. E-H: Expression of Nkx3.1 and Fem1b in seminiferous tubules of the testis at post-natal day 0, as shown at low-power (E, F) and high-power (G, H). Note that expression is limited to the germ cells (arrowheads in G, H) and is not detected in the surrounding Sertoli cells (arrows). Scale bars correspond to 100 microns.