FIGURE 2.

Generation of hiPSC lines with doxycycline-inducible expression of different subsets of reprogramming factors. A, schematic representation of the rationale followed to obtain dFib-OCT4^GFP–ind fibroblast-like cells expressing different subsets of reprogramming factors. The right panel shows the different combination of retroviruses and lentiviruses used to express the reprogramming factors. B, schematic representation showing the example of dFib-OCT4^GFP–ind-SKC that would not reprogram by only the addition of doxycycline (DOX) unless either OCT4 or a functional substitute for OCT4 was provided to the cells. C, primary hiPSC colonies obtained from dFib-OCT4^GFP after the infection with the combination of viruses depicted at the top of the images. Note that hiPSC colonies are GFP-positive. D, real-time PCR analysis was performed for the pluripotent markers OCT4, SOX2, NANOG, the reprogramming factors KLF4 and cMYC, the fibroblast marker COL1A1, and for GFP. Data are shown as relative means ± S.D. of two biological replicates analyzed in triplicate.