Fig. 7. Fertilization and development capacities of human SSCs-derived spermatids and H3K9me3 expression of embryos from round spermatids generated from human SSCs.

a–c Phase-contrast microscope showed the morphology of embryos with two pronuclei (a), embryos developing into the two-cell (b), and four and eight-cell (c) stages. Scale bars in a–c = 20 μm. The results shown in a–c were presented from at least five independent experiments. d Hierarchical clustering analysis of single-cell RNA sequencing showed the similarities in the global gene expression profiles between the embryos derived from mouse oocytes fertilized with human round spermatids of human SSCs by 3D-I and the embryos derived from mouse oocytes fertilized with mouse round spermatids. e Scatter plot revealed large scale of gene expression levels in the embryos derived from human round spermatid and mouse round spermatid. The data shown in d and e were presented from at least two independent experiments. f–h Double immunocytochemistry revealed expression of H3K9me3 and human nuclear antigen (HumNuc) in the embryos derived from human round spermatid (f) and human SSCs (g). h Replacement of primary antibodies with isotype IgGs in the embryos derived from human round spermatid served as negative controls. Scale bars f–h = 25 μm. The results shown in f–h were presented from at least three independent experiments