Updated project metadata. We show that a synthetic modified messenger RNA (smRNA)-based reprogramming method that leads to the generation of transgene-free OLs has been developed. An smRNA encoding a modified form of OLIG2, a key TF in OL development, in which the serine 147 phosphorylation site is replaced with alanine, OLIG2S147A, is designed to reprogram hiPSCs into OLs. We demonstrate that repeated administration of the smRNA encoding OLIG2 S147A lead to higher and more stable protein expression. Using the single-mutant OLIG2 smRNA morphogen, we establish a 6-day smRNA transfection protocol, and glial induction lead to rapid NG2+ OL progenitor cell (OPC) generation (> 70% purity) from hiPSC-derived neural progenitor cells (NPCs). The smRNA-induced NG2+ OPCs can mature into functional OLs in vitro and promote remyelination in vivo. Proteomic analysis of OLIG2-binding proteins indicates that OLIG2 is bound by the heat shock protein 70 (HSP70) complex. The HSP70 complex is bound more strongly to OLIG2 with the modified phosphorylation site than to wild-type OLIG2.