which consistent with prior reports5, was lower than the yield from fibroblasts of a juvenile mouse (0.1%). We characterized the fESC, ntESC, and iPSC lines for expression of Oct4 and Nanog by immunohistochemistry, and demonstrated multi-lineage differentiation potential in teratomas (Fig. 1b, c; Supplementary Fig. 1). By criteria typically applied to human samples and appropriate for a therapeutic model3, all stem cell lines manifest pluripotency.
