Targeted and stable gene delivery into muscle cells by a two-step transfersystem

We developed a muscle-specific gene delivery system based on two-step gene transfer. The first step involved adenovirus-mediated transfer of the ecotr opic retrovirus receptor (EcoRec) gene driven by the muscle-specific desmin promoter. Both human primary myoblasts and fibroblasts were efficiently tr ansduced with this adenovirus vector. However, expression of EcoRec was det ected only in myoblasts, In the second step, EcoRec-expressing myoblasts co uld be stably transduced with the ecotropic retroviral vector with the P-ga lactosidase gene. Approximately 15% of myoblasts were transduced by this tw o-step strategy, When the transduced myoblasts were differentiated into myo tubes, extensive cell-cell fusion occurred, and the apparent number of P-ga lactosidase-positive cells increased to 28%, These results indicate that ou r two-step gene delivery system could be used for targeted and stable gene transfer into muscle cells. (C) 2000 Academic Press.