Figure 6.

Trp53 knockout partially restores platelet production in Rbm8aKO^MK mice

(A) Schematic diagram showing the generation of megakaryocyte-specific Rbm8a/Trp53 double-knockout mice (for the detail, see Figure S5A).

(B) Bar graph shows platelet counts of 6- to 8-week-old mice of the indicated genotypes (mean ± SEM). N, sample number. Because most of Rbm8aKO^MK-p53^Homo mice died at 3–5 weeks of age, data were acquired from only three mice.

(C) H&E staining of bone marrow sections from mice of indicated genotypes; magnified images of representative cells are shown.

(D) Stacked-column bar graph shows the proportion (%) of megakaryocytes in bone marrow sections with different morphological features. All images were collected from three to five mice for each genotype.

(E) Dot plots show the size of megakaryocytes measured from H&E staining (1.0 = 500 μm²); for each, 100–200 megakaryocytes from three to five mice of each genotype (mean ± SEM; ns, not statistically significant, ∗∗∗∗p < 0.0001) that were measured.

(F) IHC staining of Rbm8aKO^MK-p53^Het/p53^Homo bone-marrow sections using anti-p21. Yellow arrow indicates megakaryocytes. The level of p21 was measured as in Figure 1B; ∗∗∗∗p < 0.0001.

(G) IHC was performed as in panel F using anti-phospho-H3. Red and black arrowheads indicate phospho-H3-positive and -negative megakaryocytes, respectively. The percentage of phospho-H3-positive cells was measured from three mice for each genotype (∼100 megakaryocytes); ∗∗p < 0.01.