CRISPR screen identifies ATF4 as a novel γ-globin regulator. (A) Scatter plot of the transcription factor DNA binding domain–focused CRISPR screen results. Each dot represents an sgRNA. BCL11A, LRF, and NuRD components MBD2 and MTA are expected targets that validated the screen. (B) γ-globin mRNA measured by RT-qPCR relative to AHSP (top) and as percentage of total β-like globin transcripts (bottom). Control: nontargeting sgRNA. Results are shown as mean ± standard deviation (n = 3). (C) Representative flow cytometric analysis of cells stained with anti-HbF antibody. **P < .01 by Student t test. FSC, forward scatter; RPM, reads per million; RT-qPCR, quantitative reverse transcription polymerase chain reaction; WT, wild type.