Figure 3.

Myh9 function in hematopoiesis is cell autonomous. (A) Schematic diagram of bone marrow transplantation strategy. 1 × 10⁶ BM cells were harvested from uninduced Myh9^fl/fl:Mx1-cre and control mice and transplanted into lethally irradiated wild type C57BL/6 recipient mice. Six weeks after bone marrow transplantation, three doses of poly I:C were injected to induce the deletion of Myh9 in donor-derived hematopoietic cells. Mice were analyzed 12 days after first poly I:C injection. (B) Real time PCR analysis showed deletion of Myh9 in the BM of Myh9^fl/fl:Mx1-cre recipient mice after induction of poly I:C (n = 3). (C) BM cellularity was significantly reduced in Myh9^fl/fl:Mx1-cre recipient mice compared with control mice 12 days after poly I:C injection (n = 4). (D) Peripheral blood counts were assessed at 12 days after poly I:C induction in control and Myh9^fl/fl:Mx1-cre BMT mice (n = 4). Representative dot plots (E,F,G), frequencies, and total numbers of Gr-1⁺CD11b⁺ myeloid (H), CD19⁺ B cells (I), CD71⁺Ter119^- immature erythroid cells (J), and CD71^-Ter119⁺ mature erythroid cells (K) (n = 4–5). (L) Representative contour plots of flow cytometric analysis of LK, LSK, LT-HSC, ST-HSC, MPP, GMP, CMP, MEP. Total numbers of LK and LSK (M); LT-HSC, ST-HSC and MPP (N); GMP, CMP, and MEP (O) in the BM of control and Myh9^fl/fl:Mx1-cre BMT mice 12 days after poly I:C injection (n = 4). All data are shown in bar graphs as mean ± SD. Student t test was used to compare two groups of mice (* p < 0.05,** p < 0.005,*** p < 0.001,**** p < 0.0001).