Figure 7.

Model for liver stem/progenitor cells. During development, endodermal cells from the liver bud differentiate into embryonic hepatoblasts. Later, these hepatoblasts give rise to two separate lineages, hepatocytes and cholangiocytes. Each of these two lineages is capable of self-renewal under physiological conditions. At the end of embryonic development and at the beginning of postnatal development, cholangiocyte cell lineage subdivides into two cell types that can be distinguished by the expression of the nestin-GFP transgene. We suggest that nestin-GFP expressing cells act as facultative stem cells in the adult liver.