COL1A1 and cholestasis: At 5 weeks of age, the expression of the extracellular matrix genes Col1a1 (12842) and Epcam (17075) were upregulated in DKO livers (Fig 3F, left panel), and as a consequence DKO liver displayed fibrosis as detected by Azan staining (Fig 3F, right panel); chronic hepatitis and cholestasis are known to lead to liver fibrosis [37].