Katsuhiko Hayashi et al. from Kyoto University School of Medicine have shown that female (XX) embryonic stem cells and induced pluripotent stem cells in mice can be induced into primordial germ cell-like cells (PGCLCs), which, when aggregated with female gonadal somatic cells as reconstituted ovaries, undergo X-reactivation, imprint erasure, cyst formation, and exhibit meiotic potential. Upon transplantation under mouse ovarian bursa, PGCLCs in the reconstituted ovaries matured into germinal vesicle-stage oocytes, which then contribute to fertile offspring after in vitro maturation and fertilization.

Science DOI: 10.1126/science.1226889, Sept. 4, 2012