FOXP1 rescues growth defects of PUM1 and PUM2 KD cells. (A-D) Cord blood CD34⁺ HSPCs were transduced first with pLenti-PGK-USIL DEST lentiviral vectors that encode (+) or not (−) FOXP1, and then with shCtrl (−), shPUM1 or shPUM2 vectors, and sorted at day 3 posttransduction. (A) Immunoblot analysis of the indicated proteins at day 3 posttransduction. Actin was used as loading control. (B) Relative cell expansion at day 10 posttransduction (n = 3). (C) Annexin V labeling at day 7 (shPUM1) and at day 10 (shPUM2) posttransduction. (D) CFC assay at day 7 posttransduction (n = 3). (E-G) MOLM-14 cells were transduced first with pINDUCER21 inducible lentiviral vectors that encode (+) or not (−) FOXP1, then with shCtrl (−), shPUM1, or shPUM2 vectors. The day after, FOXP1 expression was induced with doxycycline (0.05 µg/mL). (E) Immunoblot analysis of the indicated proteins at day 4 posttransduction. Actin was used as loading control. (F) Relative cell expansion of double-transduced cells at day 8 posttransduction (n = 4). (G) Annexin V labeling at day 6 posttransduction (n = 4). Data are expressed as mean ± SEM. Ns, not significant. *P < .05; **P < .01 (Student t test).