Expression of the Igll1 promoter–controlled hCD25-transgenic marker in LIN⁻ progenitors is associated with induced expression of genes linked to B-cell development. (A) A diagram of the relative relationship between the hCD25⁺ and hCD25⁻ LIN⁻B220⁻CD19⁻CD127⁺FLT3⁺SCA1^lowKIT^low progenitors to LMPPs and B-lineage cells. The diagram is based on genes differentially expressed between the hCD25⁺ and hCD25⁻ cells. The complete analysis is presented in Figure S4 (available on the Blood website; see the Supplemental Materials link at the top of the online article). (B) A dChip analysis of hCD25⁺ and hCD25⁻ LIN⁻B220⁻CD19⁻CD127⁺FLT3⁺SCA1^lowKIT^low cells in the context of LMPPs and other stages of B-cell development. Clustering shows genes being expressed in either pro-B cells or LMPPs (100 + expression units in either) and being up-regulated 1.5-fold from hCD25⁻ to hCD25⁺. Red represents high; white, intermediate; and blue, low expression of the gene indicated to the far right. Superimposed values show RMA-modeled array expression values. (C) Q-RT-PCR data from CD25⁺ and CD25⁻ cells as well as control cell populations as indicated (data from one representative experiment). The error bars indicate standard deviation. (D) The collected result of multiplex single-cell PCR on LMPPs, CLPs, pro-B cells, and hCD25^+/− LIN⁻B220⁻CD19⁻CD127⁺FLT3⁺SCA1^lowKIT^low cells as indicated. Each horizontal line of dots indicates the gene expression pattern observed in a single investigated cell. The values on top of the data panel indicate the number of positive cells and the values below the panels indicate the total number of cells analyzed. Error bars indicate standard deviation.