Induction of HbF by GG1-VP64 in erythroblasts derived from adult-mobilized PB CD34⁺ cells. (A) Schematic diagram of the empty vector control (top) and GG1-VP64-encoding vectors (bottom) where transcription is regulated by the erythroid-specific ankyrin-1 (Ank) or β-spectrin (Sp) promoters, respectively. The results obtained with 2 separate donors are shown in panels B to E. Abbreviated designation of the vectors are spectrin-ires-GFP control vector (Sp-iG), ankyrin-GG1-VP64-ires-GFP (Ank-GG1), and spectrin-GG1-VP64-ires-GFP (Sp-GG1). (B) Cell numbers as a function of time in culture after transduction. (C) Flow cytometry analysis for expression of GFP and CD235 (glyocophorin A) in erythroblasts at the end of culture where the percentages indicate the proportion of cells considered positive. (D) Hb electrophoresis of lysates from erythroblasts at the end of culture (vertical lines have been inserted to indicate a repositioned gel lane). Numbers below each lane on the images represent the VCN as determined by Southern blot analysis and densitometry analysis or quantitative PCR, for the various cell populations. (E) HPLC analysis of lysates from erythroblasts at the end of culture where the percentage of HbF is reported for each condition.