Identification and functional characterization of eel serum toxin

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K06242
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 40040:Aquatic life science-related
• Research Institution: Toho University
• Principal Investigator: Tsukada Takehiro 東邦大学, 理学部, 准教授 (50596210)
• Co-Investigator(Kenkyū-buntansha): 後藤 勝 東邦大学, 理学部, 准教授 (80379289)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: ニホンウナギ / 血清毒

Outline of Final Research Achievements

The existence of eel serum toxin (EST) has been long known, however, EST gene yet to be found. This study identified EST gene from eel genome database, and successfully cloned the full-length EST. We also established purification method from eel plasma, and found that EST was ca. 115 kDa serum protein. In vitro administration of EST strongly induced smooth muscle contraction of mouse intestine. In vivo administration of EST induced cramps on their stomach and lower limbs within a few min. These results suggest that EST targets muscles. Furthermore, second injection of EST induced severe anaphylaxis, and the mice died within 24h. Since heat-denatured EST did not have such in vitro and in vivo actions, tertiary structure of EST is important for sustaining its toxicity.

Free Research Field

魚類生理学

Academic Significance and Societal Importance of the Research Achievements

ウナギ血清毒の存在は古くから知られているが、長い間遺伝子が同定されることはなかった。本研究でウナギ血清毒遺伝子を同定し、精製法を確立したことで、ウナギ血清毒の解明に大きく近づいたことは学術的に意義がある。また、ウナギ血清毒の毒性を評価し、マウスの筋肉を強力に収縮させることがわかった。これによりウナギ血清毒研究を起点とした創薬研究へと展開できる可能性が高まり、その点で社会的な意義があるといえる。