Embryomax ksom medium amino acids

To measure protein synthesis, PS cells or mouse embryos were cultured for 1 h in 2i medium or EmbryoMax KSOM medium + amino acids (Merck Millipore) respectively, and labeling experiments were performed using Click-iT® Plus OPP Protein Synthesis Assay Kit (Life Technologies, C10456). After labeling, the samples were fixed for 15 min at room temperature in PBS supplemented with 4% paraformaldehyde and then permeabilized in PBS supplemented with 0.25% Triton X-100 for 15 min at room temperature according to the manufacturer’s instructions. Nuclei were stained with DAPI for 2 min and the cell were observed under Zeiss LSM880 fluorescence microscope. For flow cytometry, PS cells were cultured for 1 h in 2i medium supplemented with component A (Click-iT® Plus OPP Protein Synthesis Assay Kit, Life Technologies, C10456) and then were fixed for 15 min in 4% PFA at room temperature.