Gene expression analysis of myeloid and lymphoid lineage markers during mouse haematopoiesis

Summary Expression profiling of haematopoietic cells is hampered by the heterogeneous nature of haematopoietic tissues and the absolute rarity of early unrestricted progenitors. To overcome this, the expression profile of lymphoid and myeloid‐associated genes (LEF1, EBF, CD19, Sox‐4, B29, CD45, C‐fms, lysozyme, PU.1 and CD5) were investigated in 40 mouse myeloid haematopoietic precursors covering the entire haematopoietic hierarchy from multipotential to committed single lineages. The lineage‐specific expression seen in single‐cell studies was confirmed by examining fractionated bone marrow, whole tissues and differentiation of the multipotent cell line FDCP (Factor Dependent Cell Paterson) mix. Analysis of the 40 single myeloid precursors failed to detect expression of lymphoid‐associated genes, LEF1, EBF, CD19 and CD5, despite detection in lymphoid cell controls. Surprisingly, the lymphoid‐associated genes, Sox‐4 and B29 were detected in the single myeloid precursors, which was confirmed in bone marrow and a multipotential myeloid cell line. The pattern of Sox‐4 and B29, is consistent with a potential role in the commitment of bipotential granulocytic/macrophage precursors towards the granulocyte or macrophage lineage. In addition to providing baseline values for myeloid and lymphoid lineage markers during mouse haematopoiesis, these results highlight the importance of single‐cell analysis in the study of complex tissues.