Fig. 1.
Deficiencies in the TPO/Mpl pathway in MybPlt4/Plt4 mice. (A) Platelet counts and (B) circulating serum TPO levels in 8- to 12-wk-old mice of each genotype; TP indicates data from mice 16 wk after bone marrow transplant with bone-marrow donors as indicated. n = 6–21 mice per genotype. (C) Mpl expression measured by quantitative real time RT-PCR in cell populations purified by flow cytometry. Data shown are expression of Mpl relative to Hprt expression, measured by the ΔΔCt method. n = 5–8 mice per genotype. (D) Thymidine incorporation in lineage-negative (Lin−) cells from mice of the indicated genotypes after 4 d of culture in TPO. n = 5 for Mpl+/+, n = 2 for Mpl−/− mice. Data are shown as means ± SDs. ***P < 0.001; **P < 0.01; *P < 0.05; and ns, not significant, for comparisons between Mpl+/+ Myb+/+ and Mpl+/+ MybPlt4/Plt4 data.