Cf 1 mefs

CF-1 MEFs (Charles River Laboratories) were transduced with inducible STEMCCA and rtTA lentivirus–containing supernatants overnight in polybrene (8 μg/ml; Sigma-Aldrich). Doxycycline (2 μg/ml; Sigma-Aldrich) was supplemented to complete mouse ES cell medium to induce expression of OCT4, KLF4, SOX2, and c-MYC. Reprogramming was assayed by AP staining (EMD Millipore) or by flow cytometry analysis using anti–SSEA-1 (BioLegend) on BD LSRFortessa, performed according to the manufacturers’ protocols.

For generation of iPSCs from fibroblasts, CF-1 MEFs (Charles River Laboratories) were transduced with inducible STEMCCA and rtTA lentivirus–containing supernatants overnight in polybrene (8 μg/ml; Sigma-Aldrich). Cells were expanded and transduced with pLKO viruses expressing control shRNA or shRNAs targeting SOX15. Doxycycline (2 μg/ml; Sigma-Aldrich) was supplemented to ESC medium to induce expression of OCT4, KLF4, SOX2, and c-MYC. Reprogramming was assayed by AP staining (EMD Millipore) or by flow cytometry analysis using anti-SSEA1, anti-THY1, and anti-EpCAM (BioLegend) on BD LSRFortessa, performed according to the manufacturers’ protocols.
For EpiSC to ESC conversion, ∼1 × 10⁶ stable OEC-2 cells expressing SOX15 or mCherry (multiplicity of infection of 3) were plated in OEC-2 culture medium. After 24 h, medium was changed to 2i/LIF medium. 2i/LIF medium was changed every other day for 14 days.