In Vivo Transfection of Naked DNA into Tadpole Tail Muscle.

In vivo gene transfer systems are important to study foreign gene expression and promoter regulation in an organism, with the benefit of exploring this in an integrated environment. Direct injection of plasmids encoding exogenous promoters and genes into muscle has numerous advantages: the protocol is easy, efficient, and shows time-persistent plasmid expression in transfected muscular cells. After injecting naked-DNA plasmids into tadpole tail muscle, transgene expression is strong, reproducible, and correlates with the amount of DNA injected. Moreover, expression is stable as long as the tadpoles remain, or are maintained, in premetamorphic stages. By directly expressing genes and regulated promoters in tadpole muscle in vivo, one can exploit the powerful experimental advantages of gene transfer systems in an intact, physiologically normal animal.