Figure 6. Cell-permeable OCT4, SOX2, KLF4, CMYC and LIN28 induce iSC colonies (Protocol 3).

(A) Experimental timeline. Irradiated murine embryonic fibroblasts were plated at one day before (D-1) human dermal fibroblasts (HDF) (day zero, D0). Cultures were treated daily for 7 days with HDF media alone (no treatment), for 3 hours daily with 0.5 μM (each) codon-optimized recombinant proteins (RFs) or the same proteins containing MTD sequences to promote intracellular uptake (CP-RFs). Test expansion indicates when an effort was made to expand colonies in mass culture. (B) Colony morphologies and alkaline phosphatase staining.