Regulatory mechanism of starfish gonadotropin (relaxin-like gonad-stimulating peptide)

2018 Fiscal Year Final Research Report

• Project/Area Number: 16K07417
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Morphology/Structure
• Research Institution: Waseda University (2018); Tokyo Gakugei University (2016-2017)
• Principal Investigator: Mita Masatoshi 早稲田大学, 理工学術院, その他(招聘研究員) (50190674)
• Project Period (FY): 2016-04-01 – 2019-03-31
• Keywords: 生殖腺刺激ホルモン / 比較内分泌学 / リラキシン様ペプチド / G-タンパク質共役受容体 / 生殖生物学 / ヒトデ

Outline of Final Research Achievements

A relaxin-like gonad-stimulating peptide (RGP) of starfish is the first identified invertebrate gonadotropin for final gamete maturation. An antiserum against Patira pectinifera RGP (PpeRGP) was produced by immunizing rabbits. The antiserum was used for the development of a specific and sensitive RIA and ELISA for the measurement of RGP. RGP was present in the radial nerve cords and circumoral nerve rings of P. pectinifera throughout the year and its quantity is mostly the same irrespective of the breeding season. Immunohistochemical observations employing the PpeRGP antibody showed that there was lots of staining in the radial nerve cords and marginal nerves. In contrast, there did not appear to be any staining in the optic cushion. Because there are three orthologs of RGP, RGP derivatives with exchanged each A- and B-chain were synthesized chemically to analyze the interaction of RGP with its receptor. The result suggests that B-chain of RGP is involved in binding to its receptor.

Free Research Field

生殖生物学

Academic Significance and Societal Importance of the Research Achievements

生殖腺刺激ホルモンは動物における生殖腺の発達・成熟制御に重要な働きを持つ。ヒトデのリラキシン様生殖腺刺激ペプチド(RGP)は、無脊椎動物では世界で最初に同定された生殖腺刺激ホルモンでヒトの妊娠期の女性ホルモンとして知られるリラキシンとよく似た2本鎖ペプチドである。本研究の成果は、ヒトデの生殖研究分野に新たな研究基盤を確立したばかりでなく、無脊椎動物と脊椎動物にまたがるリラキシン様ペプチドとその受容体の分子共進化を知る切っ掛けとなった。