Extended Data Figure 5.

a, Immunofluorescence analysis of SOX2 (green), E-CADHERIN (red), GATA3 (magenta) and DAPI nuclear staining (blue) in mouse morula stage embryos. b, Quantification of SOX2 fluorescence intensity, normalized to DAPI intensity, in either inner or outer cells in mouse morula stage embryos (n = 93 cells from 7 embryos). Yellow arrows mark outer cells expressing only GATA3. c, Time-course immunofluorescence analysis of SOX2 (green), β-CATENIN (red), GATA3 (magenta) and DAPI nuclear staining (blue) in cow embryos at pre-compaction (n = 5), late compaction (n = 5), morula (n = 9) and expanded blastocyst (n = 5) stages. d, Immunofluorescence analysis of SOX2 (green), β-CATENIN (red), GATA3 (magenta) and DAPI nuclear staining (blue) in human pre-compaction (n = 5) and late-compaction (n = 5) stage embryos. e, Quantification of SOX2 fluorescence intensity, normalized to DAPI intensity, in either inner or outer cells in cow morula stage embryos (n = 136 cells from 9 embryos). f, Quantification of SOX2 fluorescence intensity, normalized to DAPI intensity, in either inner or outer cells in human morula stage embryos (n = 68 cells from 6 embryos). Yellow arrowheads point to outer cells expressing SOX2 and GATA3. t-test, ****p < 0.0001, ns = not significant. g, Immunofluorescence analysis of SOX2 (green), F-ACTIN (red), GATA3 (magenta) and DAPI nuclear staining (blue) in human morula and blastocyst stage embryo (n = 3 each stage). The SOX2 antibody used in panel g in this figure is MAB2018 (R&D), while the one used in Figure 2 is 14-9811-82 (Ebioscience), both show a consistent signal for SOX2. Yellow arrowheads point to outer cells co-expressing GATA3 and SOX2, while cyan arrow points to an inner cell showing SOX2 expression only. Scale bar, as displayed in figure.