Generation of Mouse Induced Pluripotent Stem Cells Without Viral Vectors
Induced pluripotent stem ( iPS) cells have been generated from\n\nmouse and human somatic cells by introducing Oct3/4 and Sox2 with\n\neither Klf4 and c-Myc or Nanog and Lin28 using retroviruses or\n\nlentiviruses. Patient- specific iPS cells could be useful in drug\n\ndiscovery and regenerative medicine. However, viral integration into\n\nthe host genome increases the risk of tumorigenicity. Here, we report\n\nthe generation of mouse iPS cells without viral vectors. Repeated\n\ntransfection of two expression plasmids, one containing the\n\ncomplementary DNAs ( cDNAs) of Oct3/4, Sox2, and Klf4 and the other\n\ncontaining the c- Myc cDNA, into mouse embryonic fibroblasts resulted\n\nin iPS cells without evidence of plasmid integration, which produced\n\nteratomas when transplanted into mice and contributed to adult\n\nchimeras. The production of virus-free iPS cells, albeit from\n\nembryonic fibroblasts, addresses a critical safety concern for\n\npotential use of iPS cells in regenerative medicine.