Figure 3: The location of germ cells was disrupted in Wt1-/flox; Cre-ERTM gonads. Wt1flox/flox females were crossed with Wt1-/flox; Cre-ERTM mice and the pregnant females were injected with tamoxifen at E9.5 to induce Cre activity. Wt1flox/flox and Wt1-/flox embryos were used as controls. Germ cells were labeled with STELLA (green, white arrows), and gonad somatic cells were labeled with GATA4 (red). The nuclei were stained in blue using DAPI. The dotted line denotes the border between the gonads and mesonephros. The arrowheads point to germ cells at the boundary between gonads and mesonephros. The gender of the embryos was confirmed with PCR using Sry primers. Testicular cords.