The zebrafish have been successfully become a popular vertebrate model for studying gene function by largescale genetic screens due to the see-through embryos and their accessibility to various experimental techniques throughout development. Furthermore, whole genomic sequence of the zebrafish genome has completely finished and its relationship to the human genomic data became clearer. The request of technological development in experiment using zebrafish must be accelerated with the increasing demand of zebrafish for understanding of the roles of specific genes involving human diseases. Here, we introduced a high-throughput injection system for zebrafish fertilized eggs to overcome the problems caused by manual injection and proposed a unique utilization of zebrafish as a host vector system of protein expression, not as a vertebrate models.

Development of antibody production technologies is necessary for diagnostic treatments and drug discovery. In general, mammals are used as host animals to produce antigen-specific antibody. However, such host animals have never produced several specific antibodies because host animals may not recognize foreign proteins. To overcome this problem, we used teleost to produce antibodies because teleost are evolutionally localized in the origin of vertebrates and have an acquired immune system in addition to the innate immune system. In particular, we attempt to produce antibody using "Bubble Eye" as a kind of goldfish (Carassius auratus), which has sacs filled with lymph liquid, as an immune animal. In this study, a recombinant EGFP-His was expressed in E. coli and then injected into Bubble Eye's sac in every two weeks. The antibodies were collected from sac instead of blood. Furthermore, a sandwich dot blotting was developed for detection of antibodies against EGFP-His. The antigen-specific antibodies were detected after 42 days from first immunization.