Multiple tissue transformation in adult zebrafish by gene gun bombardment and muscular injection of naked DNA

The efficiency of two direct gene transfer methods, gene gun (or particle b ombardment) and intramuscular injection, in transforming adult zebrafish ti ssues in vivo was examined by a noninvasive approach using green fluorescen t protein (GFP) reporter gene driven by the ubiquitously expressed human cy tomegalovirus promoter. Particle bombardment of adult zebrafish caused inte rnalization and expression of the plasmid only in the superficial layer suc h as epithelial cells, pigment cells, endothelial cells, and neurons, where as direct injection primarily transformed muscle fibers of several bundles near or around the injection site. Expression was also evident in several n onmuscle tissues, such as skin epithelia, pigment cells, blood vessel cells , and neuron-like cells. GFP expression persisted for more than 50 days wit h both methods. These observations indicate the potential of these methods for functional analysis of tissue-specific promoters, delivery of DNA vacci ne, and muscular expression of other useful genes.