Gene rescue by RPS19 restores hematopoiesis in RPS19^+/p.Q126X iPSCs. (A) Hematopoietic cells released from EBs derived from RPS19^+/p.Q126X iPSC subclones with GFP or RPS19 cDNAs integrated into the AAVS1 locus. **P = .002; n = 4 independent experiments. (B) Hematopoietic cells released from EBs, as shown in panel A, were analyzed by flow cytometry for hematopoietic lineage markers, as described in Figure 3B. **P < .01 for Ery; *P < .05 for MK and My; n = 4 independent experiments. (C) Analysis of data from panel B showing relative production of different hematopoietic lineages in the RPS19^+/p.Q126X iPSC sublines with GFP or RPS19 cDNA transgenes. Note that erythropoiesis is selectively enhanced in the RPS19-rescued cells (% CD235⁺: 21 vs 2.5, P = .009); n = 4 independent experiments. (D) Representative flow cytometry analysis showing the percentage of CD235⁺ Ery cells produced in differentiation cultures of RPS19^+/p.Q126X iPSC subclones with GFP or RPS19 cDNA transgenes. (E) The relative proportion of Ery cells produced by day 14 EBs derived from 3 WT iPSC lines, RPS19^+/p.Q126X parental iPSCs (designated as “–”) and its subclones containing GFP or RPS19 cDNAs integrated into the AAVS1 locus. The variable proportions of erythroblasts observed between the 3 WT lines represents reproducible differences in hematopoietic potential among different iPSC clones. Note that erythropoiesis is restored in RPS19^+/p.Q126X iPSCs by RPS19 cDNA, but not by GFP cDNA. *P < .05, n = 4 independent experiments comparing RPS19^+/p.Q126X + GFP and RPS19^+/p.Q126X + RPS19 clones.