Kinetic analysis of hematopoietic phenotype, progenitor function, and gene regulation in response to cytokine and BMP-4 treatment. (A) Flow cytometric analysis showing the CD45 expression of live (7AAD^-) cells comprising EBs treated with cytokines and BMP-4 at day 3, 7, 10, 15, and 22 (n = 5). (B) Summary of the total number of CD45⁺ cells and (C) total number of hematopoietic CFUs detected at day 3, 7, 10, 15, and 22 derived from one well of undifferentiated hESCs (n = 4; ^*P ≤ .01 compared to day 0; ^**P ≤ .01 compared to day 0 and day 15). (D) RT-PCR analysis of GATA-1, PU.1, and RUNX-1 transcription factors from human fetal samples, undifferentiated hESCs, purified CD34⁺CD38^-, and CD34⁺CD38⁺ human cord blood–derived stem/progenitor cells,¹³  compared to control and cytokines + BMP-4–treated EBs at day 3, 10, and 15 of differentiation. No products were detectable in the absence of reverse transcriptase (no RT negative control). Amplified PCR products were excised from gels and independently sequenced to verify correct product; n = 3 for each gene evaluated.