Cell cycle progression in Smad3-/-mice. (A) Scheme of the experimental design to study cell cycle progression in Smad3 deficient mice. Mice were sacrificed 30 minutes, 8 hours and 24 hours after receiving a single dose of BrdU (150 mg/Kg). (B) Confocal images of BrdU and pHisH3 double-labeled cells 8 hours after pulse-labeling with BrdU. BrdU/Ki-67 double-labeled cells were assessed 24 hours after BrdU injection. Scale bar 25 μm. (C) Number of cells in S phase (labeled with BrdU) 30 minutes after delivering the BrdU pulse, and of cells in the G2/M phase (double-labeled with BrdU and pHisH3) 8 hours after pulse labeling (n.s., two-way ANOVA n = 3-5 mice per genotype). (D-E) The index of cell cycle exit in wild-type and Smad3-/- mice showing an increase in the rostral DG. The index of cell cycle exit was scored by defining the ratio between BrdU+Ki67- cells and total BrdU+ cells in the DG, which corresponds to the fraction of precursors that have left the cell cycle within 24 hours (**, P ≤ 0.01, Student’s t-test, n = 5 mice per genotype).