The Choice of Expression Vector Promoter Is an Important Factor in the Reprogramming of Porcine Fibroblasts into Induced Pluripotent Cells

Porcine induced pluripotent stem cells (iPSCs) are an important animal model for development of regenerative therapies in human medicine. To date, the majority of the porcine cell lines with iPSC characteristics have been generated with the use of viral vectors harboring human or mouse reprogramming factors. Here, we report on the use of Sleeping Beauty transposon vectors based on the porcine transcription factor sequences to reprogram porcine fetal fibroblasts into iPSC-like cells. By using different promoters to drive transgenic expression, we show that the efficiency of reprogramming varies with the promoter type. The cells transfected with two different vector systems under the control of doxycycline-induced tet operator (TetO) promoters failed to upregulate essential endogenous pluripotency genes and to maintain stable iPSC morphology, whereas with the Ef1a and CAG promoters the same vectors proved efficient in generating iPSC-like cells with high levels of endogenous pluripotency gene expression that could be maintained long term in vitro. Our results suggest that the choice of expression vector promoters could significantly influence the efficiency of iPSC production from porcine somatic cells.