Oocyte production in most mammalian species is believed to cease before birth. However, this idea has been challenged with the finding that postnatal mouse ovaries possess mitotically active germ cells. A recent study showed that female germline stem cells (FGSCs) from adult mice were isolated, cultured long term and produced oocytes and progeny after transplantation into infertile mice. Here, we demonstrate the successful generation of transgenic or gene knock-down mice using FGSCs. The FGSCs from ovaries of 5-day-old and adult mice were isolated and either infected with recombinant viruses carrying green fluorescent protein, Oocyte-G1 or the mouse dynein axonemal intermediate chain 2 gene, or transfected with the Oocyte-G1 specific shRNA expression vector (pRS shOocyte-G1 vector), and then transplanted into infertile mice. Transplanted cells in the ovaries underwent oogenesis and produced heterozygous offspring after mating with wild-type male mice. The offspring were genetically characterized and the biological functions of the transferred or knock-down genes were investigated. Efficiency of gene-transfer or gene knock-down was 29%–37% and it took 2 months to produce transgenic offspring. Gene manipulation of FGSCs is a rapid and efficient method of animal transgenesis and may serve as a powerful tool for biomedical science and biotechnology.

The enrichment of female germline stem cells (FGSCs) and the establishment of cell lines are influenced by the efficiency of cell purification. A previous study using mouse vasa homolog (MVH)-magnetic bead sorting for the isolation and purification of mouse FGSCs showed a relatively low efficiency. In this study, we tested 3 further proteins with the aim of improving the efficiency of FGSC purification. Immunofluorescence assays and magnetic sorting were performed using short-type pituitary gland and brain-cadherin (Stpb-c), CD9, and interferon-inducible transmembrane protein 3 (Iftm3, Fragilis), all of which are expressed in germ cells. Although all 3 proteins were expressed in FGSCs, CD9 was unsuitable because of its lack of germline specificity, and Stpb-c was also unsuitable because of the unavailability of an appropriate primary antibody. The efficiency of FGSC purification was remarkably enhanced using the germline-specific protein Fragilis, compared with that using MVH. This new method for the purification of FGSCs may have extensive applications in stem cell studies and clinical research.

Androgen plays a pivotal role in spermatogenesis, accompanying a question how androgen acts on germ cells in testis since germ cells lack of androgen receptors (AR). Promyelocytic leukemia zinc-finger (PLZF) is essential for maintenance of undifferentiated spermatogonia population which is terminologically called spermatogonia progenitor cells (SPCs). We aim to figure out the molecular connections between androgen and fates of PLZF+ SPCs population. Immunohistochemistry was conducted to confirm that postnatal testicular germ cells lacked endogenous AR. Subsequently, total cells were isolated from 5 dpp (day post partum) mouse testes, and dihydrotestosterone (DHT) and/or bicalutamide treatment manifested that Plzf was indirectly regulated by androgen. Then, Sertoli cells were purified to screen downstream targets of AR using ChIP-seq, and gene silence and overexpression were used to attest these interactions in Sertoli cells or SPCs-Sertoli cells co-culture system. Finally, these connections were further verified in vivo using androgen pharmacological deprivation mouse model. Gata2 is identified as a target of AR, and β1-integrin is a target of Wilms’ tumor 1 (WT1) in Sertoli cells. Androgen signal negatively regulate β1-integrin on Sertoli cells via Gata2 and WT1, and β1-integrin on Sertoli cells interacts with E-cadherin on SPCs to regulate SPCs fates. Androgen promotes differentiation of PLZF+ spermatogonia pool via indirect regulatory pattern.