MMP9 is upregulated in RPS14-deficient cells resulting in decreased erythroid populations. Human BMCD34⁺ cells were transduced with lentivirus carrying shRNAs against RPS14 or Luc control. (A) After 5 days of transduction, cells were sorted for GFP+. RNA was collected and analyzed by using RT-qPCR. (B) Protein was collected from sorted cells and analyzed by using western blot analysis. β-Actin was used as a loading control. (C) RNA was collected from rps14-deficient and wild-type zebrafish embryos and analyzed by using RT-qPCR. (D) RNA was isolated from bone marrow CD34⁺ cells from patients with del(5q) MDS or healthy control subjects and analyzed by using RT-qPCR. (E) GFP+-sorted cells were cultured for an additional 2 days, and culture media were collected for an MMP9 ELISA. (F) After 7 days of transduction, cells were treated by using GolgiPlug and GolgiStop for 12 hours. Cells were stained with MMP9 antibody and analyzed according to flow cytometry. (G) Human BMCD34⁺ cells were cultured in liquid culture media. After 5 days of culture, cells were treated by rMMP9 for 2 days and analyzed for the CD71 expression by using flow cytometry. (H) Human BMCD34⁺ cells were transduced with lentivirus carrying shRNAs against RPS14 and MMP9. After 7 days of transduction, cells were analyzed for the CD71 expression by using flow cytometry. Data are representative of 3 independent transduction experiments. *P < .05, **P < .01, ***P < .001.