Sptlc1 deletion impairs myeloid differentiation in chimeric mice and compromises HSC development in competitive repopulation studies. (A-N) Studies done in chimeric noncompetitive repopulations studies. (A-F) Complete blood count (CBC) analysis of peripheral blood white blood cell (WBC), neutrophil, lymphocyte, monocyte, RBC, and platelet (PLT) counts 21 days after poly(I:C) injection for noncompetitive BMT Sptlc1^+/+ and Sptlc1^−/− mice (n = 4). (G) Total BM cellularity was determined for the Sptlc1^+/+ and Sptlc1^−/− 21 days after poly(I:C) injection in chimeric mice (n = 11). (H) Myeloid differentiation in BMCs was analyzed by Mac-1 and Gr-1 staining. (I) The total numbers of Mac-1⁺Gr-1⁺ cells were plotted for the Sptlc1^+/+ and Sptlc1^−/− (n = 11). (J) The total numbers of Ly6C⁺Ly6G⁻ cells were plotted for the Sptlc1^+/+ and Sptlc1^−/− (n = 5). (K) The total numbers of Mac-1⁺ F4/80⁺ cells were plotted for the Sptlc1^+/+ and Sptlc1^−/− (n = 5). (L) Erythroid differentiation in transplanted BMCs was analyzed by CD71 and Ter119 staining. (M) The percentage of CD71⁻Ter119⁺ cells was plotted for the Sptlc1^+/+ and Sptlc1^−/− mice (n = 11). (N) The total numbers of CD71⁻Ter119⁺ cells were plotted for the transplanted Sptlc1^+/+ and Sptlc1^−/− mice (n = 11). (O-W) Studies done in competitive repopulation studies ratio (1:8), analyzed 3 weeks after poly(I:C) injection. The percentages of donor CD45.2 cells (O), donor Lin⁻ c-Kit⁺ Sca-1⁺ (LSK) cells (P), donor ST-HSCs (Q), donor MPP cells (R), donor GMP cells (S), donor MEP cells (T), donor myeloid cells (U), donor erythroid cells (V), and donor lymphoid cells (W) of Sptlc1^+/+ and Sptlc1^−/− in competitive transplant studies were plotted. All graphs are represented as mean ± SEM. P < .05 is significant, calculated from the unpaired Student t test.