FIGURE 6.

Polyploidization is increased in p53^–/– murine Mk cell cultures. Bone marrow mononuclear cells from p53^–/– (black diamonds) and wild type (white squares) mice were cultured in the presence of recombinant human thrombopoietin for 8 days and assayed daily by flow cytometry for DNA content. Mk cells from p53^–/– mice reached higher mean ploidy levels than did cells from wild type mice (A) and were more likely to be highly polyploid (≥32 n)(B). Error bars, S.E. for two biological experiments. C, ploidy distributions are shown for the designated time points from one representative experiment for each genotype. The dashed lines indicate the ≥32 n polyploid megakaryocytes.