Figure 4: Corrected SSCs restore spermatogenesis in the testes of KitW/KitWV mice. (a) Diagram showing the repaired SSCs derived from single SSCs without off-target mutations which are selected for transplantation into infertile KitW/KitWV male mice. Two months later, spermatids are isolated from reconstituted testes and injected into mature oocytes to produce healthy mice carrying corrected Tex11 gene. (b) Testis morphology of Tex11PM/Y and HDR-1 SSC-transplanted KitW/KitWV mice. Scale bar = 100 mm. (c) Weight of Tex11PM/Y and HDR-1 SSC-transplanted KitW/KitWV testes. The average values of three separate experiments are plotted. Error bar: s.d. Significance was determined by two-tailed, unpaired Student's t-test;*P < 0.05. (d) Histological analyses of the Tex11PM/Y and HDR-1 SSC-transplanted KitW/KitWV testis. Note successful spermatogenesis in the HDR-1 SSC-transplanted testis. Scale bar = 40 μm. (e) Immunostaining of MVH in Tex11PM/Y and HDR-1-transplanted KitW/KitWV testis. Green: MVH; blue: Hoechst. Scale bar = 100 μm. (f) Round spermatids are sorted from testicular cells of reconstituted testes according to DNA content. (g) Morphology of round sperm sorted from HDR-1-transplanted testis. Scale bar = 50 μm. (h) Pups (black coat color) on 12 dpp developed from transferred two-cell embryos generated after the injection of round spermatids from HDR-1 SSCs into mature oocytes. WT: wild-type; Tex11: testis expressed 11; SSCs: spermatogonial stem cells; ROSI: round spermatid injection; s.d.: standard deviation; HDR: homology-directed repair; dpp: days postpartum.