Production of transgenic mice by random recombination of targeted genes in female germline stem cells

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.