Fig. 5. Characterization of an ES cell-derived endoderm cell line. (A) Sustained growth of endoderm cell line under serum-containing condition. The Gsc⁺ECD⁺ population was isolated by FACS and re-cultured in SCM. Cells were passaged every 3 days and cell number was measured at each passage day. (B) Morphology of a endoderm cell line after ten passages. (C) Multicolour immunofluorescent staining of the endoderm cell line after ten passages. Homogenous epithelial cells co-expressing ECD, Gata4, Foxa2 and cytokeratin 18 are present. (D) Stable expression of endoderm markers in the cell line. The expression pattern of this cell line is almost identical to that of endoderm cells on day 26 in Fig. 3D.