At the day of transfection, 1 × 10 7 HEK293 cells in each P15 dish (nine dishes in total) were transfected by the CaPO 4 co-precipitation method with pRSV-REV, pMD.2G, pMDGP-Lg/pRRE plasmids and a lentiviral vector (pLM-fSV2A, Addgene ID 27512 [ 18 ]) expressing the four Yamanaka factors (OCT4, KLF4, c-Myc and SOX2) polycistronically.
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