Hexim1 OE promotes fetal globin expression. (A) Selected top enriched gene sets from gene set enrichment analysis including GATA1 target genes, heme metabolism, and fetal liver genes. (B) Expression changes of known regulators of γ production (Lin28b, Arid3a, Tal1, Bcl11a, Myb, Fut8, and Sox6) via RNA sequencing from Murphy et al.¹ (C) RNA expression changes of globin genes in HUDEP-2 in HEXIM1 OE cell lines compared with EV controls via RNA sequencing from Murphy et al.¹ (D) Ratio of γ-globin to total β-globin transcripts in HUDEP-2 cells in expansion media (left) and at maturation day 5 (right). (E) Western blot of γ-globin levels in HUDEP-2 cells at maturation day 10 in HEXIM1 OE and EV cell lines. A representative western blot (left) and quantification (right) are shown. (F) RNA expression of γ-globin in CD36⁺ primary erythroblasts. Data are presented relative to 18S ribosomal RNA. (G) Quantification of F-cells in EV, HEXIM1 OE, and Y2A OE lines by fluorescence-activated cell sorting analysis in CD36⁺ primary erythroblasts. (H) Histogram showing distribution of cells expressing different HbF levels. (I) Median HbF expression of the F-cell population. (J) Bcl11a expression in CD36⁺ primary erythroblasts in indicated cell lines. Data are presented relative to 18S ribosomal RNA. n = minimum of 3 replicates; ∗P < .05; ∗∗P < .005; ∗∗∗P < .0005. ns, not significant.