Figla-Cre Transgenic Mice Expressing Myristoylated EGFP in Germ Cells as a Model for Investigating Perinatal Oocyte Dynamics

This technology includes a transgenic mouse model which can be used to study perinatal oocyte dynamics. In the first two days after birth, the number of primordial ovarian follicles and their germ cells undergo a major decrease. The mechanism for this decrease was studied. Ablation of FIGLA (Factor in the germline, alpha), a basic helix-loop-transcription factor, results in massive perinatal oocyte loss. A transgenic mouse line was established, Figla-EGFP /Cre, in which EGFP and Cre recombinase are expressed just before birth in germ cells. When Figla-EGFP /Cre mice were crossed with mTomato/mEGFP (where m = myristoylated) mice, red Tomato was excised in germ cells, and EGFP fluorescence was observed in both cytosol and on the plasma membrane. Somatic cells remained red because mTomato continued to be expressed. Results indicate that oocyte loss is due to caspase-dependent apoptosis, rather than autophagy or exit.