Fig. 5. Absence of pancreatic cilia and increased polycystin-2 expression in orpk mice. In wild-type pancreatic sections (A) polycystin-2 expression is localized in intercalated ducts. Cilia were visualized using an antibody against acetylated tubulin. Cilia are confined to the lumen of intracinar and intercalated ducts (arrows). Acini (a) and intercalated ducts (id) are outlined in yellow and white, respectively, for better visualization. Inset shows Hematoxylin/Eosin staining of acini in wild type. A dramatic decrease in cilia number is detected in orpk mice (B; arrow). Polycystin-2 expression in orpk mice is increased and mislocalized in intracinar dilated ducts. An acini with a severe intracinar ductal dilation is outlined in yellow. Dilated intracinar ducts (outlined in red), a structure that is not found in wild-type pancreas, show high polycystin-2 expression, comparable to levels that are only observed in intercalated ducts of control mice. Inset shows Hematoxylin/Eosin staining of a dilated intracinar duct in orpk mice. Cilia are also present in islets in wild-type mice (C), but are almost absent in orpk mice (D; arrow). Cilia are present at embryonic stages (E15.5) in wild type (E) but very few could be detected in orpk mice (F). Cilia length, shown in µm, is reduced in orpk mice (G). Tissue sections were derived from three different animals at each stage. Errors bars are shown as ±s.d. a, acini; id, intercalated duct; dd, dilated ducts.