Figure 1

Characterization of mouse embryonic stem cells cultured on human foreskin fibroblast without exogenous leukemia inhibitory factor. (A) Morphology of E14 mouse embryonic stem cells (ESCs) cultured on human foreskin fibroblast (HFF) without exogenous leukemia inhibitory factor (LIF) for 20 passages. (a), (b) Bright field of E14 mouse ESCs on HFF. (c), (d) Alkaline phosphatase (AKP) staining of E14 mouse ESCs on HFF. Scale bars: (a), (c) 1,000 μm; (b), (d) 200 μm. (B) Quantitative analysis of the AKP-positive colonies of E14 mouse ESCs cultured on HFF without exogenous LIF at passages 5 and 9, respectively; n = 3. (C) Immunofluorescence staining of E14 mouse ESCs on HFF without exogenous LIF using antibodies against Oct4, Sox2 and Nanog, respectively. Scale bars: 25 μm. 4',6-Diamidino-2-phenylindole (blue) staining was used to indicate the nucleus. (D) H & E staining of the teratoma formed by E14 mouse ESCs cultured on HFF without exogenous LIF for 16 passages. The teratoma contains (a) intestinal epithelium, (b) smooth muscles, (c) cartilages and (d) neural epithelium. Scale bars: 50 μm. (E) Chimeric mice obtained post injection of E14 mouse ESCs cultured on HFF without exogenous LIF for 16 passages into blastocysts of C57BL/6 mice. Brown color denotes origination of the E14 cells.