(a) Experimental scheme for xenotransplantation experiments, purification and downstream analysis of donor-derived cells. (b) Testicular expression of NuMA (red) and Flag-Ddx3y (green) in non-xenotransplanted, busulfan-treated mice. (c) Expression of NuMA (red) and Flag-Ddx3y (green) in xenotransplanted seminiferous tubules. NuMA and Flag-Ddx3y are co-stained with Vasa and nuclei are counter-stained with DAPI (blue). Top row is DDX3Y-rescued donor cells and bottom row, mutant GCLCs. (d) Top, percentage efficiency in engraftment of NuMA+ donor cells. Bottom, percentage of NuMA+/Vasa+ cells in seminiferous tubules of testis transplanted with both DDX3Y-rescued iPSCs and AZFa-deleted mutant iPSCs. Totally, 3 independent xenografts were quantified per donor cell line. (e) Detection of Utf1, Cherry and Vasa proteins in xenotransplants from rescue (iAZFΔa+DDX3Y-FL-mCherry) and mutant (iAZFΔa+mCherry) lines. A merged image of all three channels and DAPI-stained nuclei (blue) is accompanied by individual images of each protein and DAPI in gray scale. (f) Detection of Cherry, Stella, Dazl and Daz proteins in xenotransplants from rescue (iAZFΔa+DDX3Y-FL-mCherry) to the right and mutant (iAZFΔa+mCherry) lines to the left of the panel. Merged images are shown with DAPI-stained nuclei in blue.