Fig. 2. Increased proliferation in a neural stem cell niche in the absence of p53. More cells incorporate BrdU (A-C) and display immunoreactivity to the M-phase specific epitope phospho-histone H3 (D-F) in the lateral ventricle wall (LVW) of p53^-/- mice compared with wild-type littermates. The number of TUNEL labeled apoptotic cells was not significantly different between wild type and p53^-/- mice. Numbers represent LVW positive nuclei per brain section. Positive nuclei were counted on serial coronal sections of the anterior horn of the lateral ventricle within a defined space of the subventricular zone. (H) Quantification of the proportion of LVW cells capable of forming primary neurospheres. ^*P<0.05, ^**P<0.01. Scale bars: 10 µm.