RDTR/SCFHA-LVs target gene transfer into hCD34⁺ cells in BM of FA patients. BM MCs of 3 different FA patients (FA-P1, FA-P2, and FA-P3 shown in panels A, B, and C, respectively) were incubated with 2 different vector preparations of RDTR/SCFHA-displaying or VSV-G/SCF–displaying LVs. As controls, the FA BM MCs were incubated with LVs displaying RDTR or VSV-G in the presence of rSCF (50 ng/mL); MOI = 10 was applied for all transductions. RetroNectin was added for all transductions except where indicated (n.d. indicates not done). At day 3 after transduction, cells were evaluated for CD34⁺ staining and GFP expression by FACS. (D) Transduction of total BM of a FA patient incubated with 6 different vector preparations of RDTR/SCFHA-displaying LVs or 2 different preparations of VSV-G/SCF–displaying LVs. At day 3 after transduction, cells were evaluated for hCD34⁺ cell-surface expression and GFP expression by FACS. (E) Comparison of transduction (GFP⁺) of hCD34⁺ cells 3 days after transduction and their derived CFCs 14 days after myeloid differentiation from total BM of FA-P3 to confirm stable transduction. (F) Total BM of a FANC-A patient was transduced with RDTR/SCF-displaying control vector encoding for GFP (SFFVEGFP) or a correcting vector encoding for FANCA and GFP (SFFVFAIEG). Total BM cells were transduced at MOI = 10. At day 3 of transduction, 1 × 10⁵ total BM cells were cultured in methylcellulose that supported myeloid differentiation in the presence and absence of mitomycin C (10nM). GFP⁺ colonies per 1 × 10⁵ seeded cells were scored.