西亚试剂： doxycycline-inducible lentivirus encoding all four factors

To increase the infection efficiency, we used a doxycycline-inducible lentivirus encoding all four factors Oct4, Klf4, Sox2, and c-Myc from a polycistronic expression cassette (pHAGE2-TetOminiCMV-hSTEMCCA) (Sommer et al., 2010). Blood cells were simultaneously infected with a constitutively active lentivirus encoding the reverse tetracycline transactivator (FUW-M2rtTA) (Hockemeyer et al., 2008) as well as the polycistronic vector. Infected blood cells were transferred onto feeder layers of mouse embryonic fibroblasts (MEFs) and cultured in the presence of IL-7 or G-CSF, GM-CSF, IL-6, and IL-3 and 2 μg/ml doxycycline (Dox) for an additional 4 days (Figure 1A). At day 5 after Dox induction, the cells were transferred to human ESC medium containing 2 μg/ml Dox, and 25–40 days later colonies were picked and expanded.