80 Depletion of NANOS3 causes germ cells loss in pig fetal gonads of both sexes

Germ cells are of fundamental hereditary importance for the next generation. In the early pre-gastrulation stages, primordial germ cells (PGCs) arise from outside the gonads. The PGC subsequently migrate toward the genital ridge—the future gonads. In mouse models, the nos family gene, NANOS3, was found to be expressed in the migrating PGCs and play a role in protecting PGCs from both sexes from undergoing apoptosis. In this study, we investigated the role of NANOS3 in pigs—an important agricultural model. We have generated homozygous NANOS3 gene (NANOS3^−/−) knockouts by CRISPR/Cas editing in male and female fetal fibroblasts followed by somatic cell nuclear transfer. Although the knockout of NANOS3 did not impair the survival or growth of embryonic and gonadal developments, it led to a marked delay or disruption in the testicular and ovigerous cords, which can be recognised in the age-matched wild-type fetuses at Day 35 of gestation (d35). By immunostaining with pluripotency and germ cell-specific markers, we found that ablation of NANOS3 resulted in the number of migrating PGCs (Day 18) and subsequently resulted in the complete loss of PGCs in both fetal ovaries and testis after gonadal sex differentiation (d35). This study confirms that NANOS3 is required for the survival of germ cells in both sexes.