Fig. 6.
Phospho-specific flow cytometric analysis of phosphoprotein expression in Chk1-deficient T cells. (A) Specificity of the anti-p-p53 Ab. Thymocytes from WT or p53-null mice that had been treated with 5 Gy or sham irradiation were stained with anti-CD25, anti-CD44, anti-Lin, and anti-p-p53 (Ser-15) Ab. Levels of phosphorylated p53 were determined by phospho-specific flow cytometry. (B) Phospho-specific flow cytometric analysis of DN2 and DN3 subpopulations in Lck-Chk1fl/fl mice. Intracellular staining for p-p53 (Ser-9 and Ser-15), p-Chk1 (Ser-317), p-Chk2 (Thr-387), and p-Brca1 (Ser-1423) was performed for mice of the indicated genetic backgrounds. (C) Phospho-specific flow analysis of DN2 and DN3 thymocytes from Lck-Chk1fl/fl mice in a Chk2-null background. Intracellular staining for p-Chk1 (Ser-317) and p-p53 (Ser-9 and 15) was performed for mice of the indicated genetic backgrounds.