Figure 3. Elevated Mdmx impairs the early DNA damage response signal.
p53−/− (A–D, F) or p53−/−Mdm2−/− (A–C, E, F) MEFs were infected with a bicistronic retrovirus encoding YFP alone (vector, V), YFP and full-length HA-Mdmx (Mx) or YFP and HA-MxΔRING (MxΔR). A, B, D–F) Following exposure to 5 Gy of γIR, MEFs were fixed at the indicated intervals and immunofluorescence for γH2AX (A, B) or pS/T-Q (D–F) was performed. The number of foci per cell was quantified. (A, D, E) The mean of at least three independent experiments is graphed. Error bars represent SEM, and significance determined using a confidence interval of 95%. (B, F) Ranking of γH2AX (B) and pS/T-Q (F) foci in individual cells was graphed for a representative experiment in both MEF genotypes. C) Western blot analysis of whole cell lysates for the proteins indicated to the left of the panels at the indicated intervals following γIR.