Expression of siRNA-resistant RPS19 rescues proliferation and erythroid differentiation. (A) The RPS19 transgene in the lentiviral construct pLV-mRIY has 24 bases changed to make it resistant to silencing by the RPS19-siRNA B, while producing the wild-type protein. SFFV indicates spleen focus-forming virus promoter. (B) LV-TH-RPS19-B-transduced cells show rescued proliferation and erythroid differentiation 7 days after transduction with the LV-mRIY (RPS19 rescue) vector. Transduction with the control vector LV-YFP (YFP) does not improve the proliferative or erythroid defect. Neither vector has any effect on LV-TH-Scr-transduced cells. Representative FACS profiles from 2 separate experiments are shown. Percentages represent the fraction of cells in each quadrant.