Figure 6.

Oocyte-specific deletion of Med12 causes infertility without affecting folliculogenesis. (A) Breeding strategy used to assess the effects of Med12 deficiency on folliculogenesis with Gdf9-Cre that is active in oocytes of primordial (smallest) ovarian follicles, and Zp3-Cre that is active in oocytes of primary follicles. Gdf9-Cre introduced from the male side never produced Gdf9-Cre positive pups likely due to leaky Gdf9-Cre expression from the paternal side that inactivated Med12 floxed allele from the maternal side and caused embryonic lethality (D). (B, C) Periodic acid-Schiff staining of 12-week-old Med12^fl/fl and Med12^fl/fl Zp3-Cre ovaries generated in crosses described in (A). Note the presence of normal follicles at all stages as well as corpora luteua in both Med12^fl/fl and Med12^fl/fl Zp3-Cre mice. Med12^fl/fl Zp3-Cre mice are infertile. (D–G) Fertility results from various breeding strategies depicted in (A) are shown. Note lack of mortality when Zp3-Cre is transmitted from the male side (G) as opposed to Gdf9-Cre (D) (D, n = 7; E, n = 5; F, n = 4; G, n = 3). ^****P < 0.0001. Scale bars = 100 μm.