Figure 1. Lentiviral vector design and experimental strategy used in the generation of hiPSC from CB-derived CD34+ HSPCs.

(A) Structure of the policistronic lentivector used for iPSC generation. EF1α is the constitutive promoter. The four reprogramming factors (Oct4, Klf4, Sox2, c-myc; OKSM) are expressed as independent transcripts through the 2A and IRES sequences. The small blue arrows identify the primers used to determine the silencing of the ectopic expression of the reprogramming factors. (B) Timeline of fibroblast and CB-CD34+ reprogramming. CD34+ cells were MACS-isolated and pre-stimulated with hematopoietic cytokines. Two days later, CB-CD34+ cells were infected. After 3 days, infected cells were transferred onto feeders. Small adherent colonies were observed around day 8–9. hESC-like colonies were identifiable after 10–15 days.