Figure 6.

The Heterotopic Glands Emerge from the IFE, Outer Root Sheath, and Follicular Matrix

Immunohistochemistry on mid-ventral skin sections from postnatal K14-Cre; Smo^f/f mutants showing Shh (A, D, and G), keratin 8 (K8; [B, E, and H]), keratin 14 (K14; [C, F, I, and L]), keratin 6 (K6; [J]), and smooth muscle α-actin (ASMA; [K]) proteins. The anti-Shh antibody labels both Shh and Indian hedgehog (Ihh) proteins.

(A–F) The heterotopic glands (hg) developing from hair follicles (A–C) and the hg emerging directly from the IFE (D–F) are Shh/Ihh negative and K8 positive. By contrast, the HF are Shh positive and K8 negative. Both the HF and hg are K14 positive.

(G–J) The hg developing from the follicular matrix are Shh/Ihh negative and K8-, K14-, and K6 positive.

(K) An ASMA-positive myoepithelium (my) around luminal cells of an hg.

(L) K14-positive duct cells (du) of an orthotopic mammary gland. Scale bar: 50 μm.