Alteration of the BM microenvironment by Gsα-deficient osteocytes is necessary to induce myeloproliferation. (A) BM transplantation schema from control to lethally irradiated OCY-GsαKO mice or (F) vice versa. (B-E) PB cell counts of 7-week-old control donor and OCY-GsαKO recipient mice before transplantation and recipient mice 4 and 9 weeks after transplantation showing (B) number of leukocytes, (C) % neutrophils, (D) number of platelets, and (E) number of lymphocytes. (G-J) PB cell counts from 7-week-old OCY-GsαKO donor and control recipient mice before transplantation and recipient mice 4 and 9 weeks after transplantation showing (G) number of leukocytes, (H) % neutrophils, (I) number of platelets, and (J) number of lymphocytes (n = 3 for donors and n = 8 for recipients). (K-L) LKS (Lin⁻ c-Kit⁺ Sca-1⁺), LKS SLAM (Lin⁻ c-Kit⁺ Sca-1⁺ CD150⁺ CD48⁻), MPPs (Lin⁻ c-kit⁺ Sca-1⁺ Thy1.1⁻ Flk-2⁺), CMPs (IL-7Rα⁻ Lin⁻ c-kit⁺ Sca-1⁻ FcγR^lo CD34⁺), GMPs (IL-7Rα⁻ Lin⁻ c-kit⁺ Sca-1⁻ FcγR⁺ CD34⁺), and MEPs (IL-7Rα⁻ Lin⁻ c-kit⁺ Sca-1⁻ FcγR^lo CD34⁻) in (K) BM and (L) spleen from control and OCY-GsαKO female mice (n = 6). (M) Strategy for methylcellulose colony formation assay. (N-O) Myeloid colonies from (N) 2 × 10⁴ BM cells and (O) 1 × 10⁵ spleen cells from 8- to 10-week-old control and OCY-GsαKO mice (n = 4). Error bars represent mean ± SEM. *P < .05 by t test compared with donor.