The meiosis was blocked in germ cells of 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. Control (Wt1flox/flox and Wt1-/flox) and Wt1-/flox; Cre-ERTM gonads were dissected at E13.5 and cultured in vitro for 3 days. MVH/SYCP3 (A–D) and MVH/γH2AX (E–H) double-staining experiment was performed, and germ cells were labeled with MVH (green). DAPI (blue) was used to stain the nuclei. The gender of the embryos was confirmed with PCR using Sry primers.