Defective megakaryocyte maturation in the absence of Plk1. (A) Bone marrow sections from 8-week-old mice were stained with hematoxylin and eosin (H&E) or antibodies against Plk1 or the VWF. Scale bars, 100 μm (insets, 20 μm). (B) The quantification of VWF area per cell is shown in the histogram. Horizontal bars indicate the average from >500 cells per condition from at least 3 different animals. ***P < .001; Student t test. (C) Phosphorylation of pH3 in Plk1-deficient or control megakaryocytes. Scale bars, 100 μm (insets, 20 μm). The quantification of pH3-positive cells is shown in the right histogram. Data are mean ± standard deviation (SD; n = 3 mice per genotype). ***P < .001; Student t test. (D) Representative images of mitotic cells in Plk1-deficient or control mice after staining with H&E or immunodetection of pH3. Scale bars, 20 μm. (E) Analysis of nuclear complexity in Plk1-null and control megakaryocytes (MKs). Scale bars, 20 μm. In these analyses, at least 250 cells from ≥3 different animals per genotype were used. Student t test; ***P < .001.