(A) PAS staining of WT, Sohlh2–/–, and CCS2 Sohlh2–/– ovaries at P21. Hematoxylin was used for counterstaining (n = 3 per group). Scale bars: 50 μm. (B–D) RNA expression of Sohlh2, EGFP, and Sohlh1. Sohlh2 was fused with EGFP, and expression of EGFP showed that the Ddx4-Cre promoter was active in Sohlh2–/– ovaries. However, overexpression of Sohlh2 in Sohlh2–/– ovaries could not rescue Sohlh1 expression (n = 6 per group). Error bars indicate the mean ± SD. Data are representative of at least 3 independent experiments.