Figure 2.

Rbm14 knockout induces apoptosis and cell cycle arrest of post‐implantation epiblast. A, Representative immunofluorescent images of both wild type and Rbm14 knockout embryos at E6.0 stage for the apoptosis marker active caspase‐3 (red) and the epiblast marker OCT4 (green). The nuclei were counterstained with 4′,6‐diamidino‐2‐phenylindole (DAPI) and are shown in in blue. Scale bar, 50 μm. Elevated apoptosis is detected in the Rbm14 knockout embryo, and most of the active caspase‐3⁺ cells co‐express OCT4. B, Representative immunofluorescent images of both wild type and Rbm14 knockout embryos at E6.0 stage for the G2/M phase marker histone H3 (phospho S10) (red) and BrdU (green). The nuclei were counterstained with DAPI and are shown in blue. The epiblast regions of the embryos are outlined with white dotted lines. Scale bar, 50 μm. BrdU were injected into the pregnant female mice intraperitoneally and were incorporated into the mitotic cells at S phase. The embryos were dissected from the uterus of pregnant female mice 1 h later. C, Quantification of the immunostaining shown in (A). Three sections for each group were analysed. Data are shown as mean ± SEM. ***P < .001, Student's t‐test. D, E, Quantification of the immunostaining shown in (B). The proportion of BrdU⁺ cells decreased in the Rbm14 knockout E6.0 epiblast. Three sections from three different embryos for each group were analysed (n = 3). Data are shown as mean ± SEM. *P < .05, Student's t‐test