Generation of exogenous germ cells in the ovaries of sterile NANOS3-null beef cattle

Blastocyst complementation (BC) systems have enabled in vivo generation of organs from allogeneic pluripotent cells, compensating for an empty germ cell niche in gene knockout (KO) animals. Here, we succeeded in producing chimeric beef cattle (Wagyu) by transferring allogenic germ cells into ovaries using somatic cell nuclear transfer and BC technology. The KO of NANOS3 (NANOS3(−/−)) in Wagyu bovine ovaries produced a complete loss of germ cells. Holstein blastomeres (NANOS3(+/+)) were injected into NANOS3(−/−) Wagyu embryos. Subsequently, exogenous germ cells (NANOS3(+/+)) were identified in the NANOS3(−/−) ovary. These results clearly indicate that allogeneic germ cells can be generated in recipient germ cell-free gonads using cloning and BC technologies.