Oocyte-specific Smc2 knockout causes female infertility
To address the role of Smc2 , we generated specific knockout mice with a deletion of Smc2 in oocytes from primordial follicle stage using Cre transgene driven by Gdf9 promoter (Gdf9-Cre ) (Fig. 1A). The Smc2 deletion was confirmed by RT-PCR in MII oocytes isolated from the ovaries ofSmc2flox/flox andSmc2flox/flox Gdf9-Cre females (Fig. 1B).
To determine whether maternal SMC2 is essential for fertility, we crossed Smc2flox /flox Gdf9-Cre females withSmc2flox /flox males for six months to analyze the fertility and found that theSmc2flox /flox Gdf9-Cre females are completely infertile (Fig.1C). To clarify the reason for infertility, we collected oocytes fromSmc2flox /flox Gdf9-Cre females. The number of oocytes was normal (Fig. 1D), and they underwent germinal vesicle breakdown (GVBD) and showed first polar body extrusion (PB1E) at rates similar to the wild type (Fig.1 E and F).