Fig. 6. Expression of Jag1 and Notch2 proteins during bile duct differentiation. (A,B) Immunohistochemistry of sections of livers at P3. (A) Jag1 immunoreactivity is detected in both endothelial cells and non-endothelial supporting cells of portal veins and hepatic arteries. (B) Notch2 immunoreactivity is detected in groups of cells (arrowheads) that appear to be adjacent to the Jag1-expressing cells. (C) Jag1 immunoreactivity is detected in cells surrounding the hepatic arteries and portal veins at P8. (D) The same section as in C, showing DBA immunofluorescence, demonstrates that Jag1 protein is not expressed in bile duct epithelial cells. (E,F) Notch2 immunohistochemistry of sections of livers at E18 of wild-type littermate (E) and Notch2^del1/Notch2^del1 homozygous mutant (F) embryos. No differences in the numbers or distribution of Notch2-positive cells are observed. Concentrations of Notch2-positive cells adjacent to the developing portal triads are indicated by arrowheads.