Development of Platform Technology for Sterile Control of Genetically Modified Fish

^○Shao-Yang Hu¹, Hong-Yi Gong¹, Erez Raz², Koichi Kawakami³, Gen-Hwa Lin¹, Jen-Leih Wu¹

1) Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, Taiwan, 2) Germ Cell Development, Max Planck Institute for Biophysical Chemistry, Gottingen, Germany, 3)Division of Molecular and Developmental Biology, National Institute of Genetics, Mishima, Japan

  Since the 1985 when the first transgenic fish was successfully established, the transgenic fish of various species are being actively investigated worldwide for improving the economic benefit in aquaculture. However, no any transgenic fish had been sold on the market to date except the ornamental fish. The main impediment to commercialize the transgenic fish is unfinished assessment of food safety and ecology impacts. The ecological impacts focus on the issues concerning gene flow and the escape of transgenic fish which may cause the extinction of wild natural fish stocks. In view of this issue, sterile control turn into a core technology to solve the theme of aquatic genetically modified organism release to the natural environment. In the present study, we use zebrafish as model to establish a sterile platform by ablation of primordial germ cells (PGCs) and oocytes. Here, a 5 kb askopos (kop) promoter with PGCs specificity and a 2.2 kb zona pellucida (zpc) promoter with oocytes specificity were cloned to trigger KillerRed expression and the transgenic lines called kop:KillerRed and zpc:KillerRed were established. KillerRed is a red fluorescent protein capable of generating reactive oxygen species (ROS) upon light irradiation and leading to cell apoptosis. The deficient gonad or undeveloped offspring were shown in zpc:KillerRed transgenic line after light irradiation. The fish without gonad was obtained in kop:KillerRed after ablation of PGCs using red light irradiation. In contrast to the transgenic fish irradiated with light, the development of gonad is normal in transgenic fish without light irradiation. These results provide an inducible platform to control the infertility of GM fish and offer economic benefits for maintenance of superior breeds in aquaculture purpose.