Methylation patterns and hematopoietic phenotypes of gene-corrected MPS-IPS and their hematopoietic progeny. (A) Bisulfite sequencing of the OCT4 and NANOG promoters in gene-corrected KC-derived MPS-iPS cells from P1, their hematopoietic progeny, and human umbilical cord blood cells. Open circles denote unmethylated CpGs, and filled circles represent methylated CpGs. CpG position relative to the downstream transcriptional start site is shown above each column. Sequencing reactions of specific amplicons are represented by each row of circles. (B) When plated in semisolid methylcellulose medium (100 000 total unsorted cells per experiment), colony-forming units (CFUs) formed. CFUs from iPS-derived hematopoietic cells were compared with wild-type bone marrow cells (6 independent experiments were performed, mean ± SEM, 480 ± 32). Wild-type (WT) bone marrow cells formed significantly more colonies than hematopoietic derivatives of WT iPS cells, MPS-iPS cells, and gene-corrected MPS-iPS cells (all P < .01). There was no significant difference, however, among the number of CFUs from uncorrected MPS-iPS–derived hematopoietic cells (MPS iPS, 12 experiments were performed), corrected MPS-iPS–derived hematopoietic cells (MPS iPS IDUA, 10 experiments), and the WT iPS-derived hematopoietic cells (WT iPS, 6 experiments): 166 ± 34 versus 147 ± 24 versus 71 ± 8; all P > .05. (C) The examples of granulocyte/macrophage CFU (CFU-GM), erythroid CFU (CFU-E), and mixed CFU (CFU-mix) are shown. (C) Images were taken with an Olympus CK2 microscope, magnification 4× EA4 0.10 160/−. Images were taken with a Nikon Coolpix 4300 digital camera with a microscope adaptor from Martin Microscope MMCOOL S/N:1228 Nikon UR-E4. All images were taken at room temperature.