Screening of genes that promote expansion of hematopoietic cells from hESCs/hiPSCs. (A) Hematopoietic fractions derived from hESCs in EB culture used in this study. (B) Schematic representation of the protocol modified for efficient induction of pre-HPCs/HPCs from hESCs/hiPSCs in EB culture. (C) Expression of BRACHYURY, RUNX1, and TAL1/SCL expression during differentiation of hESCs in EBs determined by quantitative RT-PCR analysis. mRNA levels were normalized to GAPDH expression. Expression levels relative to that in hESCs (day 0 of EB culture) are shown as the means ± SD for triplicate analyses. (D) Cell growth of CD34⁺CD43⁻ cells from day 6 EBs and CD34⁺CD43⁺ cells from day 8 EBs. EBs were formed by suspension culture of hiPSCs. Sorted cells (2 × 10⁴) were transduced with the indicated hematopoietic regulator genes and cultured on OP9 cells in the presence of 20 ng/mL of SCF and TPO. At day 14 of culture, the absolute numbers of cells were determined and are indicated in bars. Representative data from repeated experiments are shown. (E) Expression of SOX17 during differentiation of hESCs in EBs determined by quantitative RT-PCR analysis. mRNA levels were normalized to GAPDH expression. Expression levels relative to that in hESCs (day 0 of EB culture) are shown as the means ± SD for triplicate analyses. (F) Expression of SOX17, SOX7, and SOX18 in bulk EB cells, CD34⁺CD43⁻ cells (ECs), CD34⁺CD43⁺CD45⁻ cells (pre-HPCs), and CD34⁺CD43⁺CD45⁺ cells (HPCs) from day 8 EBs determined by quantitative RT-PCR analysis. mRNA levels were normalized to GAPDH expression. Expression levels relative to those in CB CD34⁺ cells are shown as the means ± SD for triplicate analyses.