GFP(PAX5)⁺B220⁺GR-1/MAC-1⁺ cells coexpress lymphoid and myeloid programs at the single-cell level. (A) Polyclonal IgH chain D to J (DJ) recombination was detected in BM cells but not in the GFP(PAX5)⁺B220⁺GR-1/MAC-1⁺ cell populations from experiments 1, 2, 3, 5, and 6 analyzed by PCR. The analysis used a set of 3 primers designed to amplify either the germline (GL) gene or any recombination event between D regions and J1-J3. (B) Expression of mb-1, Cebpe, and Hprt in cells from populations (sorted by FACS) of common myeloid progenitors (CMPs), granulocyte-macrophage progenitors (GMPs), megakaryocyte-erythrocyte progenitors (MEPs), as well as, pro-B and DP T-cell progenitors (pro-T). (C) Co-expression of mb-1 and Cebpe in single GFP(PAX5)⁺B220⁺GR-1/MAC-1⁺ cells, as evaluated by multiplex single-cell RT-PCR.¹⁹  Asterisk indicates water control.