Fig. 3.
The DNA damage response in Xrcc2−/− embryos occurs in G2/M cells of the VZ. Xrcc2 deficiency leads to p53 ser18 phosphorylation (A) and p53 stabilization (A Inset) in a layer of cells at the margin (arrowheads) of the ventricle (V) of an E14.5 embryo. (B) No p53 phosphorylation or stabilization (Inset) is found in WT embryo. (C) The cartoon represents the characteristic position of the progenitor cell nucleus within the VZ as the cell cycle progresses. (D) Cells that are immunopositive for phosphorylated histone H3 staining (green signal) indicate cells in mitosis, and BrdU-positive cells (red signal) mark those in S phase (arrowheads). The VZ and the postmitotic SVZ are marked.