Fig 1: A reversed developmental trajectory of germ cell in SSC reprogramming. (A) UMAP plot showing the integration of single-cell transcriptome data from successful branch of SSC reprogramming (DMSO- and 5C groups), mouse in vivo germ cells and gonadal somatic cells from E6.5 to PND5.5. Grey dots indicate in vivo germ cells or germline somatic cells, colored dots or triangles with black outline indicate reprogramming cells or ESCs. (B) Scmap projection of the successful branch of SSC reprogramming (left, 5C group; right, DMSO group) and mouse in vivo germ cells. The color key from bright yellow to dark blue indicates low to high ratio of projected cells. SPG, spermatogonia; in vivo GC dev., in vivo germ cell development. (C) Heatmap showing the expression of DEGs of in vivo germ cell development and their expression dynamics in SSC reprogramming, GO terms enriched in both processes were highlighted. (D) Violin plots showing the expression levels of canonical marker genes of in vivo germ cells in the successful branch of SSC reprogramming. (E) Immunofluorescence of Oct4-EGFP (green) co-stained with RHOX5 (top, red) and L1TD1 (bottom, red), respectively, in domed colonies during SSC reprogramming. Scale bar, 50 μm. (F) Immunofluorescence of Oct4-EGFP (green) co-stained with PRDM14 (pink) and TFAP2C (red) in domed colonies during SSC reprogramming. Scale bar, 50 μm. (G) Immunofluorescence of Oct4-EGFP (green) co-stained with OTX2 (red) in domed colonies during SSC reprogramming. Scale bar, 50 μm. (H) Immunofluorescence of Oct4-EGFP (green) co-stained with PRDM14 (pink) and OTX2 (red) in domed colonies at different time points during SSC reprogramming. Note, * The diameters of detected colonies. Scale bar, 50 μm. (I) Boxplot showing the number of PRDM14(+)OTX2(–), PRDM14(+)OTX2(+), PRDM14(–)OTX2(+) colonies (left) and their percentage (right) in OG(+) colonies at different time points during SSC reprogramming, corresponding to Fig. 4H. See also Fig. S4.