Fig. 3.

By embryonic day (E) 12.5, the pattern of membrane β-catenin expression correlates with sex-specific compartmentalization and vascularization of the gonad. A–D, I–K: Within the testis, two distinct compartments form (A). Membrane β-catenin-negative cells (B,C, DAPI, arrow) are seen adjacent to the vasculature (PECAM-1, red), and these cells together partition the membrane β-catenin-positive cells. (Germ cells are yellow where β-catenin and PECAM-1 colocalize. CV, Coelomic blood vessel.) β-catenin-negative cells constitute the interstitial compartment, marked by Pdgfr-α (D; arrowhead in inset indicates epithelium), MAFB (J), and C-MAF (K), and are mutually exclusive with β-catenin-positive cells. E–H, L–N: In the ovary, a matrix appearance is maintained with membrane β-catenin-positive cells throughout. Vasculature branches off the mesonephric vessel (F,G, lower arrowhead, DAPI not shown) and is flanked by largely membrane β-catenin-positive cells. Pdgfr-α delineates a β-catenin-negative region at the mesonephric–ovarian border (H, arrow), but not within the ovary itself. MAFB and C-MAF are perivascular (M,N). I–N: Boxes in I and L correspond to the regions boxed in matching colors in J,K and M,J, respectively, and are enlarged in right-hand panels of each.