Transfer and expression of hG6PD in mouse G6PD null ES cells.

(A) Biochemical correction of the G6PD null phenotype. After retroviral transduction wild-type (WT) ES cells show an hG6PD band of comparable intensity to the endogenous murine band. In G6PD null ES cells no G6PD activity is visible before transduction; after transduction only the hG6PD band is seen. (B-D) Functional rescue of the G6PD null phenotype in undifferentiated ES cells. (B) For WT ES cells (n = 5) the cloning efficiency (%) was very similar in untransduced (43 ± 2.4) and in transduced cells (37.1 ± 3.1). By contrast, for G6PD null ES cells the cloning efficiency (n = 5) is only 2.4 ± 0.5 (C), but it is restored (n = 5) to 16.2 ± 2.2 after transduction (D). (E-G) Functional rescue of the G6PD null phenotype in differentiating EB. (E) WT ES cells (n = 2) formed high numbers of EB (133.3 ± 11.8 and 121.7 ± 14/1000 cells in untransduced and in transduced cells, respectively). By contrast, G6PD null ES cells formed only 3.9 ± 1.9 EB/1000 cells (F), but this was restored (n = 6) to 123 ± 12 after transduction (G). U indicates untransduced; T, transduced; WT, wild-type ES cells; null, G6PD null ES cells.