Fig. 1

Morphological comparison of iPSCs derived from two types of MEFs and the identification of pluripotency. a, a′ Morphology of S-MEFs and MEFs. b, b′ Primary iPSC colony formed 12 days after transduction. c, c′ Established P 3 iPSC clones. d, d′ AP staining performed for P 8 iPSCs. e Statistical analysis of AP⁺ colonies generated from Day 6 pre-iPSCs during the reprogramming process. **Significant differences at p < 0.01. f Identity differentiation of mouse S-iPSCs in vivo. The nude mouse was injected with S-iPSCs (black arrow indicates the teratoma). Teratoma with all three germ layers determined by H & E staining was observed. g Immunofluorescence of pluripotency marker genes (Oct4, Nanog, and SSEA-1) in S-iPSCs. Nuclei were counterstained with DAPI. Scale bars = 25 μm. AP alkaline phosphatase, D day, iPSC induced pluripotent stem cell, MEF mouse embryonic fibroblast, P passage