The effects of recombinant Oct4 and Sox2 proteins on pluripotent genes expression in mouse somatic cells

Abstract

Mouse and human somatic cells can be reprogrammed into induced pluripotent stem (iPS) cells by reretroviral transducing genes encoding four transcription factors: Oct4, Sox2, Klf4 and c-Myc. This provided an opportunity to generate patient-specific pluripotent stem cells for human therapeutic and research application. However, a major limitation of this technology is the viral genome integration. In this study we demonstrated that recombinant protein Oct-4, one of the four key factors for reprogramming, containing protein transduction domain can pass through somatic cell membrane when added to the culture media. Treating mouse embryonic fibroblast with recombinant Oct-4 protein resulted in an activation of Nanog-luciferase reporter. Surprisingly, when using Tat-Oct4 protein combine with three retroviral vectors: Sox2, Klf4 and c-Myc, could be generated iPS colonies from primary mouse fibroblasts. These results suggest that the recombinant Oct-4 protein is active and may be used to substitute viral vector in iPS cell generation.