FIG. 1.

Transduction of NIH 3T3 cells and A375 human melanoma cells by RGD₁₃ viruses. NIH 3T3 and A375 human melanoma cells were infected with an RGD virus and then selected with G418 for 2 weeks, fixed, and stained with Giemsa, and the colonies were counted. The amphotropic virus, Amph, was generated by expressing the amphotropic envelope, pCAA, and the ecotropic virus, Eco, was generated by expressing the wild-type ecotropic envelope, pCEE. Note the log scale. The pCAA expression vector was generated by removing the amphotropic envelope gene from the full-length infectious clone(17) and insertion into pCEE after removal of the ecotropic envelope. The packaging construct, LAPNL, was generated by removal of the VSV-G envelope from LGRNL (30) and insertion of the secreted alkaline phosphatase gene (SEAP; Tropix). Pseudotyped virus producer cell lines were generated by cotransfection of Anjou 65 cells with LAPNL and a plasmid expressing a chimeric envelope derivative using Dotap (Boehringer), followed by selection in zeocin (200 μg/ml) for 2 weeks. RGD₁₃ required cotranfection of a zeocin expression plasmid (Invitrogen).