Figure 4.

Zn-finger domain of MdmX suppresses genome instability in p53-deficient human cells. (a) DNA content determined by propidium iodide staining of human breast tumor MB157 cells transduced with MdmX FL or deletion mutants. DNA content of experimental cells (red histograms) was superimposed over the DNA content of Mock control cells (blue histograms). (b) Metaphase spread analysis for chromosome number per cell (in indicated ranges) in transduced MB157 human breast tumor cells. At least 50 metaphases were scored per cell line. (c) Summary of chromosome analyses showing cell fraction with larger than triploid genome in population of transduced MB157 cells. Error bars represent mean±s.d. from three to four experiments with at least 50 metaphase cells scored per experiment. (d) Frequency of pseudo-bipolar mitosis expressed as a percent of total mitotic events in population of MdmX-transduced MB157 cells. Spindles with amplified centrosomes clustered around the opposite pools (see Figure 3d, right panel) were scored as pseudo-bipolar mitosis. Results from five experiments with more than 100 mitotic events per experiment are shown in Box-whiskers plots. (e) Frequency of multipolar spindles in the populations of transduced MB157 cells. More than 200 mitotic spindles were scored per experiment. Error bars represent mean±s.d. from average of five experiments for each cell line. P-values relative to Mock control: **P<0.005; *P from 0.005 to 0.05, unpaired t-test.