Fig. 4. Promoter activity in EpCAM-positive cells. P0 cells in early (4-7 day) intermediate (14-21 day) and late (30 day) cultures. (a) Cells with advancement along fibroblast-like morphology. (b-d) GFP expression in P0 cells transduced with lentiviral vector using PGK, Alb and TTR promoters. (e,f) Late P0 cultures with CK-19 staining (e, red color) and merged image showing coexpression of GFP under TTR promoter (f, green color=GFP; arrows indicate CK-19-GFP coexpressing cells). (g,h) Epithelial cells in P3 cultures with merged images of CK-19 immunostaining and GFP under either TTR (g) or Alb promoter (h) (arrows). DAPI nuclear counterstain (blue). Magnification: x200.