The transcriptional architecture of early human hematopoiesis identifies multilevel control of lymphoid commitment.

Here we tracked transcriptome changes over ten human hematopoietic stem and early progenitor populations, defining the transcriptional dynamics underlying the first steps of commitment. Most of the transcriptional programs observed extended beyond lineage boundaries. In particular, multi-lymphoid progenitors (MLPs) presented a hybrid transcriptional state with elements of lymphoid and myeloid programs, but also stem cell characteristics. Total RNA was obtained from flow-sorted populations of human cord blood based on the cell surface expression of CD34, CD38, CD45RA, Thy1, and CD49f, CD10, CD7, CD19 and CD1a.