ATF4 links HRI to BCL11A and γ-globin production. (A) Immunoblot analysis of differentiated HUDEP2 after depletion of HRI. (B) BCL11A mRNA levels measured by quantitative reverse transcription polymerase chain reaction (RT-qPCR) in indicated cells. Results are shown as mean ± standard deviation (SD; n = 3). (C) Immunoblot analysis of HUDEP2 upon depletion of ATF4. (D) Immunoblot analysis of undifferentiated HUDEP2 cells treated with 2.5 μg/mL of tunicamycin for 3 days. (E) BCL11A and γ-globin mRNA levels measured by RT-qPCR in parental or ATF4 overexpressing (ATF4 OE) undifferentiated HUDEP2 cells. Results are shown as mean ± SD (n = 4). (F) γ-globin mRNA levels measured by RT-qPCR with overexpression of BCL11A-ER in differentiated HUDEP2 cells. Results are shown as mean ± SD (n = 3). **P < .01 by Student t test. WT, wild type.