Fig. 3. Abnormal gonadal morphology in both male and female Pod1 mutants. (A) At 12.5 dpc, gonads from XY Pod1 KO mice (bottom) were smaller than in the wild-type testes (top). (B) Gonads from a Pod1 KO XX embryo at 12.5 dpc also were reduced in size compared with the control. In both XY and XX Pod1 KO embryos, an abnormal invagination of the surface was observed at the anterior region of the gonad (g) (arrowheads). g, gonad; m, mesonephros. (C-F) Semi-thin sections from 13.5 dpc gonads were stained with Toluidine Blue. At 13.5 dpc, the wild-type XY gonad (C) showed organized testicular cords (tc), peritubular myoid cells (pm) and extensive mesenchyme (m). However, no organized testicular cords, peritubular myoid cells or mesenchyme were seen in Pod1 KO XY gonads (E). At 13.5 dpc, Pod1 KO XX gonads (F) showed a similar arrangement of germ (g) and somatic (s) cells as the control (D), but lacked the small but distinct mesenchymal zone near the coelomic epithelium. tc, testicular cord; pm, peritubular myoid cell; m, mesenchyme; ce, coelomic epithelium; g, germ cell; s, somatic cell.