Overexpression of RPS19 in CD34⁺ DBA cells improves erythroid colony formation.

CD34⁺ BM cells from patients with DBA (Patients 1-4) andnormal healthy donors were transduced with the oncoretroviral vectors MRIG or MGIN. Since the cells were grown with cytokines during prestimulation and transduction, the colony frequency is different than presented for the fresh cells in Figure 1. (A, B) A quantity of 1000 transduced, sorted progenitor cells (CD34⁺/GFP⁺ cells) from 4 patients (Patients 1-4, Table 1) was grown in methylcellulose as described in “Materials and methods” with erythropoietin as the only growth factor present. CFU-Es (A) were scored on day 7 and BFU-Es (B) on day 14. We analyzed 4 to 6 plates for each experiment to derive the mean and SEM. Hatched bars indicate the number of colonies from MGIN-transduced cells. Black bars indicate the number of colonies from MRIG-transduced cells. White bars indicate the number of colonies from mock-transduced, unsorted cells. Colony frequencies generated by the cells transduced with the control vector and the MRIG vector were significantly different for each patient (P < .03) using the Wilcoxon rank sum test. (C, D) A quantity of 1000 transduced progenitor cells (GFP⁺ and CD34⁺ cells) was grown in methylcellulose in the presence of erythropoietin and SCF. CFU-E (C) and BFU-E (D) colonies were scored on day 7 and day 14, respectively. We analyzed 3 plates for each experiment to derive the mean and SEM. Colony frequencies generated by the MRIG vector–transduced cells were significantly higher when compared with those generated by the control vector in patients 1-3 (P < .005, Wilcoxon rank sum test), but no difference was seen in patient 4.