Phenotype of Rps19- and Rpl11-deficient erythroblasts. (A) Rps19 and Rpl11 protein levels in I/11 erythroblasts 3 days after transduction with lentiviral vectors expressing scrambled (Sc) shRNA or 2 distinct shRNAs (A-B) specific for Rps19 or Rpl11, respectively. (B) RNA profiles measured by absorbance at 254 nm in a sucrose gradient loaded with cytoplasmic extract of shRNA-treated erythroblasts 3 days after transduction. The positions of the 40S and 60S ribosomal subunits, the 80S monosome, and polysomes are indicated (for peak identification, see supplemental Figure 1). (C) I/11 erythroblasts were transduced with lentiviral shRNA constructs as indicated. Cells were cultured for 3 days (left panel) and 6 days (middle panel) in proliferation conditions or switched to differentiation conditions 3 days after transduction and differentiated for 4 days (right panel). Cells were stained for hemoglobin (brown) and histological dyes. Full arrowheads point to multinucleated cells; empty arrowheads point to aberrantly differentiated cells. Scale bars represent 25 μm.