Teratoma-susceptible germ cells express markers of germ cell pluripotency and male germ cell differentiation. (A-F) Teratoma-susceptible germ cells express pluripotency (A,B) and differentiation (C-F) markers. Oct4::GFP transgenic FVB, 129 and M19 germ cells from E13.5-E15.5 gonads were FACS-isolated and gene expression was analyzed by qPCR (n=4-15). Female germ cell expression data from all strains was statistically similar and pooled. Gene expression at all embryonic time points is plotted relative to expression in E13.5 FVB male germ cells. *, P<0.05; †, P<0.005; ‡, P<0.0005.