Zonal differences of GFAP and GFAP-reporter expression in control and CDE treated mice in contrast to alpha-smooth muscle actin. Immunohistochemistry of GFAP in liver sections of control (A) and CDE treated mice (A'). In B and B' the reporter enzyme Cre-recombinase has a nuclear localisation and was therefore used to demonstrate GFAP-promoter activity in CDE treated mice (B') compared to controls (B). HSCs are identifiable by their long, slender GFAP positive appendages. Biliary cells (black arrows) are also decorated with GFAP respectively express the Cre reporter. Under CDE conditions a third cell type, oval cells (brown, white arrows), express GFAP. The expression pattern of GFAP and GFAP-reporter in the periportal region of liver lobulus (A', B') is completely different from that in the pericentral region (D), (Cre in pericentral region is not shown, because there was no staining). Oval cell clusters, identifiable by their ductular formation, are surrounded by alpha-smooth muscle positive cells (C).