Induction of insulin-expression in hTERT-FPC by Pdx1-LV. (a) shows schematic of LV with rat Pdx1 and GFP genes driven by hPGK promoter - IRES, intervening internal ribosomal entry site, cPPT, central polypurine tract, Wpre, posttranscriptional regulatory element of the woodchuck hepadnavirus. (b) shows Pdx1-LV-transduced hTERT-FPC under phase contrast (top) and under epifluorescence for GFP. (c) shows flow cytometric quantitation of GFP in nontransduced cells (top panel) and Pdx1-LV-transduced hTERT-FPC. MFI = mean fluorescence intensity. (d) shows RT-PCR for gene expression in control hTERT-FPC (lane 1), Pdx1-LV-transduced hTERT-FPC cultured without serum (lane 2) and without serum plus activin A (lane 3), and mature pancreatic islets (lane 4). (e) shows insulin and c-peptide expression in negative control hTERT-FPC-Pdx1 cells, where primary antibodies were omitted, and cells with expression of both insulin and c-peptide. Orig. Mag., × 200.