Significance
Transfer of sperm-producing stem cells isolated from a donor male into testes of a recipient male has important applications for preserving germplasm and as a conduit for widespread dissemination of desirable genetics in livestock production. A key aspect is surrogate males that lack endogenous germline but are otherwise physiologically normal. Here we demonstrate that male mice, pigs, and goats rendered genetically sterile by CRISPR-Cas9 editing of the NANOS2 gene support donor-derived spermatogenesis following allogeneic stem cell transplantation. In addition, we show that CRISPR-Cas9 editing of the NANOS2 gene in cattle leads to male germline ablation. These findings represent a major advance toward surrogate sires becoming a tool for disseminating and regenerating germplasm in all mammals.
Abstract
Spermatogonial stem cell transplantation (SSCT) is an experimental technique for transfer of germline between donor and recipient males that could be used as a tool for biomedical research, preservation of endangered species, and dissemination of desirable genetics in food animal populations. To fully realize these potentials, recipient males must be devoid of endogenous germline but possess normal testicular architecture and somatic cell function capable of supporting allogeneic donor stem cell engraftment and regeneration of spermatogenesis. Here we show that male mice, pigs, goats, and cattle harboring knockout alleles of the NANOS2 gene generated by CRISPR-Cas9 editing have testes that are germline ablated but otherwise structurally normal. In adult pigs and goats, SSCT with allogeneic donor stem cells led to sustained donor-derived spermatogenesis. With prepubertal mice, allogeneic SSCT resulted in attainment of natural fertility. Collectively, these advancements represent a major step toward realizing the enormous potential of surrogate sires as a tool for dissemination and regeneration of germplasm in all mammalian species.
