Promotion of Direct Reprogramming by Glis1

Induced pluripotent stem cells (iPSC) are generated from somatic cells by the transgene expression of three transcription factors Oct3/4, Sox2, and Klf4 (OSK), albeit at a low efficiency. The protooncogene c-Myc enhances the efficiency of iPSC generation by OSK, but it also increases the tumorigenicity of the resulting iPSC. In the current study, we found the Gli-like transcription factor Glis1, when expressed together with OSK, to markedly enhance the generation of iPSC from both mouse and human fibroblasts. Mouse iPSC generated by OSK and Glis1 can form germline-competent chimeras. Glis1 is enriched in unfertilized oocytes and one cell-stage embryos. DNA microarray analyses revealed that Glis1 promotes multiple pro-reprogramming pathways, including Myc, Nanog, Lin28, Wnt, mesenchymal-epithelial transition (MET), and Esrrb. These results therefore demonstrated that oocyte transcription factor Glis1 effectively promote direct reprogramming during iPSC generation. p53-null mouse embryonic fibroblasts were transduced with OSK and OSK+Glis1 and were used for microarray analyses.