Cell cycle properties and progenitor number in the mutant dentate gyrus.

<p>(A-B) After BrdU labeling, E15.5 pregnant mice were sacrificed 1 h later to retrieve fetal brains for subsequent fixing and sectioning. Immunofluorescence microscopy was performed with anti-Ki67 and-BrdU antibodies, with representative images of the hippocampal regions shown in (A) and the quantification of the stained cells in two regions (outlined with dotted lines) presented in (B). The quantification was based on two pairs of control and mutant brains, with 8 matched sections per brain. In the dentate neuroepithelium (dNE), no difference was detected. In the dentate migration stream (dms), the number of BrdU⁺ progenitors was normal but the Ki67⁺ cycling cells increased significantly, thereby decreasing the ratio of S-phase (BrdU⁺) vs proliferating (Ki67⁺) cells. (C-D) Immunostaining of sections from the same brains as in (A-B) with an antibody specific to phospho-Ser10 of histone H3 (pH3). Representative images of the hippocampal regions are shown in (C) and the quantification of positive cells in two regions (outlined with dashed lines) is presented in (D). No pH3-positive cells were detected in the migration stream. Scale bars: 100 μm; ns, not statistically significant; *<i>p</i><0.05, **<i>p</i><0.01.