tNGFR expression after transduction of CD34⁺ progenitors with HOXA5 and control vectors. Numbers shown are the percentage of total cells expressing tNGFR (%MC192⁺/total cells) and the percentage of CD34⁺ cells expressing tNGFR (%MC192⁺CD34⁺/total CD34⁺cells) from 12 experiments (mean ± SEM). (A) and (B) show typical FACS profiles of cultures 24 hours after transduction with either theHOXA5 vector or control vector, respectively. The R1 gate was used to isolate MC192⁺CD34⁺ cells for further culture and analysis. (C) Isotype control. (D) Mock (nontransduced) control.