Fig. 5. Immunohistochemistry showing the regional distribution of prominin-1 in murine epididymis. (A) Histology of adult murine epididymis stained with toluidine blue showing the ductuli efferentes (de), initial segment (is), distal caput (dc) and part of the corpus (c). (B,C) Transverse cryosections of adult murine epididymis were double immunolabeled with mAb 13A4 (13A4) and I3 antiserum (I3) followed by Cy3-conjugated anti-rat and Cy2-conjugated anti-rabbit secondary antibodies. Nuclei were labeled with Hoechst dye. Asterisks mark spermatozoa. Arrows indicate the apical surface of the cauda epithelium without prominin-1 immunostaining. All fluorescence images are at the same magnification. Scale bars, 100 µm. (D) Cryosections of cauda were immunolabeled with mAb 13A4 followed by peroxidase-coupled goat anti-rat, and observed using Nomarski optics. Asterisks mark spermatozoa. Boxes indicate the apical surface of the cauda epithelium without prominin-1 immunostaining. Scale bar, 40 µm.