Expression pattern of Ikbkap during oogenesis and impact of deletion on fertility. (A) Immunofluorescence staining showing the levels of IKAP in the oocytes of primary, secondary and antral follicles. Ovaries from control (Ctrl) and Ikbkap mutant (CKO) mice were stained with anti-IKAP antibody. The sections were counterstained with DAPI to visualize DNA. Oocytes are indicated by arrows. Scale bar, 50 μm. (B) Graph shows the fold induction of Ikbkap mRNA levels in unfertilized GV, MII oocytes, and various stages of embryos compared with the values of GV oocytes. Quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR) was performed. Gapdh was used as an internal control. (C) Gapdh and Ikbkap mRNA levels in Ctrl and CKO MII oocytes. (D) Fertility analysis of Ctrl and CKO female mice. Females were crossed with wild-type males. Litter size is shown as the number of pups per litter. Horizontal lines are the mean. Data are presented as mean ± standard error of the mean (SEM). *p < 0.05; **p < 0.01; ***p < 0.001.