(A) Different developmental stages (E8.5 to E10.5) of wild-type (+/+) and Trip12 mutant (mt/mt) embryos. (×magnification) (B) The somite number of Trip12+/+, Trip12+/mt, and Trip12mt/mt embryos. The somite number of each embryo at E9.5 was scored by stereo microscopy. **, p<0.001; N.S., not significant. (C) Hematoxylin and eosin staining of sections of wild-type (+/+) and Trip12 mutant (mt/mt) embryos at different developmental stages (E7.5 to E9.5). Placental tissues at E9.5 are enlarged in the right panel. Scale bars represent 1 mm. (D) The expression levels of negative cell cycle regulators in wild-type (+/+) and Trip12 mutant (mt/mt) embryos. Total RNA was isolated from embryos, and the gene expression profiles were analyzed using real-time RT-PCR. Data are presented as the mean+s.d., n = 3. **, p<0.001; N.S., not significant.