Expression of vectors in cell lines.

Fold increase in MFI of GFP in (A) the nonhematopoietic 293A cells, (B) the fetal hemoglobin-expressing K562 cells (mean ± SD, n = 4), and MFI/proviral copy number in (C) the adult-type hemoglobin-expressing MEL cells transduced with the SIN-lentiviral vectors. The ratio between MFI of transduced and nontransduced cells was used to determine the fold-increase in MFI (y-axes). The vectors are color-coded by promoters. MEL cell data are shown before (solid bars) and after (hatched bars) HMBA-induced differentiation after normalization for copy number from a representative experiment.