Flow cytometric analysis of HOXB4GFP expression on human cord blood cells following 2 weeks of culture under different conditions. Data from 1 representative experiment is shown. (A) A significantly higher percentage of transduced cells cocultured with DL-expressing OP9 cells show higher GFP expression than cells cultured in DL conditioned media or fresh media. (B) Confirmation that this phenomenon is not observed with control conditioned media or control coculture.