Fig. 9. Liver fragments of knockout fetuses develop cystic structures in the testes of Scid mice. Liver fragments of 12.5-day wild-type and knockout fetuses were transplanted and maintained for 2 months in the testes of Scid mice, and histologically and histochemically analyzed for expression of cell type-specific markers. The wild-type liver developed normal hepatic tissues, in which the portal vein and hepatic vein differentiated (A,B). Hepatocytes store PAS-positive glycogen. Periportal biliary cells (arrows) are immunostained for bile duct-specific cytokeratin (C), type IV collagen (E) and nidogen (F) but are negative for DBA-binding sites (D). By contrast, the knockout liver developed abundant cystic structures strongly expressing bile duct markers in the testis (G-L). Normal hepatic tissues are also observed with cystic structures in a few knockout transplants (G; Hematoxylin and Eosin staining). HV, hepatic vein; PV, portal vein. Scale bars: 50 µm.