Transduction of human CFU-Cs with GALV, RD114, or FeLV-C pseudotyped retroviral vectors. Slot blot analysis of 1.0 mL virus-containing medium was used to compare the titer of the different virus preparations (top panel). Human CD34⁺ peripheral blood CD34⁺ cells were transduced with GALV, RD114, or FeLV-C pseudotyped retrovirus particles. Transduced CFU-Cs were identified by PCR analysis of DNA extracted from each colony. Data shown was pooled from 3 experiments. Error bars indicate standard deviation.