Introduction of a foreign gene into medakafish using the particle gun method.

We developed a procedure to introduce a foreign gene into fertilized eggs of medakafish (Oryzias latipes) using the particle gun method, which is one of the easiest and most reliable techniques for gene transfer. A plasmid construct with the green fluorescence protein (GFP) gene driven by the madakafish beta-actin gene promoter was successfully introduced into eggs, and the expression of GFP was observed in 20% of the primary transfectant (chimera) fish. In addition, germ line transmission of GFP was observed in 13% of the GFP-positive primary transfectant fish. The new application described here should enable us to investigate gene expression using the fish model on a routine basis without high technical sophistication. J. Exp. Zool. 287:285-293, 2000.