Medakafish (Oryzias latipes) belongs to a group of small oviparous teleost fishes that inhabit fresh water in Asian countries including Japan. Experimental procedures to introduce foreign genes into medakafish have been reported using electroporation and/or microinjection. Microinjection is widely used in gene transfer experiments. However, it requires high technical sophistication. Electroporation can be easily applied to gene transfer experiments, but with a low efficiency. Therefore, we attempted to develop an experimental procedure to introduce a foreign gene without high technical sophistication but at reasonably high efficiency. A particle gun is an instrument used to introduce DNA that is coated on gold microcarrier particles directly into cells at high speed using high-pressure gas. Here we report a procedure to introduce a foreign gene into fertilized eggs of medakafish using the particle gun method. A plasmid construct with the green fluorescence protein (GFP) gene driven by the medakafish beta-actin gene promoter was successfully introduced into eggs, and the expression of GFP was observed in 20% of the primary transfectant fish. In addition, germ line transmission of GFP was observed in 13% of the GFP-positive primary transfectant.12th International Sympojium on Bioluminescence and Chemiluminescenc
