Fig. 1

Generation of human induced pluripotent stem cells (iPSCs) with episomal vectors. (a) Schematic diagram of the protocol used to obtain iPSCs by transient introduction of episomes carrying OCT3/4, SOX2, KLF4, L-MYC, and LIN28 transcription factors and dominant negative mutant of p53 protein into human somatic cells. (b) Exemplary result of iPSC colony formation. Changes in cellular morphology during iPSC colony formation in urinary epithelial cells between days 13 and 19 after the initial transfection are shown. Arrows indicate the emerging embryonic stem cell-like colonies throughout the reprogramming experiment. Scale bar = 100 μm. (c) Alkaline phosphatase stainings of iPSCs generated from neonatal fibroblasts, adult scar tissue fibroblasts, amniotic fluid cells, and urinary epithelial cells at days 21, 28, 28, and 14, respectively, after the initial transfection with episomal plasmids. BJiPSCs (iPSCs derived from BJ cells), StiPSCs (iPSCs derived from scar tissue fibroblasts), AmiPSCs (amniocyte-derived iPSCs), and UiPSCs (iPSCs reprogrammed from urinary epithelial cells) are shown. (d) Efficiencies of iPSC colony formation in fibroblastic and epithelial cells transfected with reprogramming vectors. The efficiencies were calculated as number of colonies positive for alkaline phosphatase activity divided for total cell number plated for the experiment