Figure 2

OSKR iPSCs Are Pluripotent and Can Produce Chimeric Mice.

(a) Phase contrast and Oct4-GFP images of iPSC colonies generated from the retroviral transduction of OG2 MEFs with OSKR (bar = 500 μm). (b) q-PCR analysis of pluripotency genes expression in OSKR iPSC (OSKR iPS-2). The expression levels were normalized to those observed in G4 ESCs (n = 3). (c) Silencing of integrated transgenes in OSKR iPS-2. Three days after retroviral infection of MEFs with reprogramming factors, the expression of the exogenous factors could be detected using qPCR primers specific to the transgenes. In fully reprogrammed OSKR iPSCs, the expression of transgenes could not be detected (n = 3). (d) Immunofluorescence staining of pluripotency markers (Oct4, Nanog, Sox2 and SSEA1) in OSKR iPSCs (bar = 20 μm). (e) Hematoxylin and eosin staining of teratomas derived from OSKR iPSCs (bar = 100 μm). (f) EB-mediated in vitro differentiation assay performed on OSKR iPSCs. Differentiated cells stained positive for Gata6 (endoderm), Nestin (ectoderm) and α-smooth muscle actin (mesoderm) (bar = 100 μm). (g) Chimeric blastocysts after injecting OSKR iPSCs into 8 cell stage embryos (bar = 100 μm). (h) A two-week-old chimeric mouse was derived from OSKR iPSCs and the photograph of the mouse was taken in our Laboratory Animal Center by Dr Yangli Pei. Relative expression was quantified using the comparative threshold cycle (Ct) method (2^−ΔΔCt). The ΔCT was calculated using β-actin as internal control.