Mcl-1 is uniquely up-regulated in the HSC fraction of reconstituted human hematopoietic cells. (A) Experimental strategy used to examine the protein expression of Bcl-2 family members in de novo isolated and reconstituted human hematopoietic cells. (B) Quantitative flow cytometric analysis of Bcl-2 family member protein expression in each population within the human hematopoietic hierarchy in both de novo isolated and in vivo reconstituted human hematopoietic cells. The average protein expression of Bcl-2, Bcl-xL, and Mcl-1 in each population of the hematopoietic hierarchy relative to isotype control is shown. Protein expression is the mean fluorescence intensity (MFI) relative to the isotype control. Error bars represent the mean ± SEM of 3 independent experiments. *P < .05, **P < .01. (C) Representative examples of flow cytometry analysis used to assess the frequency of primitive CD34+ human hematopoietic cells that express Bcl-2, Bcl-xL, and Mcl-1. Frequencies represent the percentage of cells positive for the respective protein and CD34 expression ± SEM. Plots are representative of at least 3 independent experiments.
