A perspective on fish gonad manipulation for biotechnical applications

The gonad is an essential organ for gen- erating sperm and ova in vertebrates. This review describes several pilot studies on gonad gene manipulation and development in fish. With antisense RNA techniques, we suppressed the gonad devel- opment, and thus the fertility, of an antisense gonad- otropin-releasing hormone (sGnRH) transgenic common carp. Then, using a tissue-specific exoge- nous gene excision strategy with sexual compensa- tion, we knocked out the gonad-specific transgene. Under the control of the rainbow trout protamine promoter, the transgenic fish expressed the reporter gene eGFP specifically in the spermary. These re- sults indicate that the fish gonad is a new model or- gan that can improve contemporary biotechnology experiments. Herein we discuss the potential of fish gonad manipulation for resolving important biosafety problems regarding transgenic fish generation and producing the new transgenic animal bioreactor.