title: A new relaxin-like gonad-stimulating peptide identified in the starfish Asterias amurensis.
abstract: Relaxin-like gonad-stimulating peptide (RGP) of starfish Asterina pectinifera was the first invertebrate gonadotropin to have its chemical structure identified. However, it is unclear whether gonadotropic hormones in other species starfish are relaxin-like peptides. Thus, this study tried to identify the molecular structure of gonadotropic hormone in Asterias amurensis. As a result, we identified A. amurensis gonadotropic hormone as the RGP (AamRGP). The DNA sequence encoding AamRGP consisted of 330 base pairs with an open reading frame encoding a peptide of 109 amino acids (aa), including a signal peptide (26 aa), B-chain (20 aa), C-peptide (38 aa) and A-chain (25 aa). Comparing with A. pectinifera RGP (ApeRGP), the amino acid identity levels between AmaRGP and ApeRGP were 58% for the A-chain and 73% for the B-chain. Furthermore, chemical synthetic AamRGP induced gamete spawning and oocyte maturation in ovarian fragments of A. amurensis. In contrast, the ovary of A. pectinifera failed to respond to the AamRGP. This suggested that AamRGP is a new relaxin-like peptide.
authors.affiliation: Department of Biology, Faculty of Education, Tokyo Gakugei University, Nukuikita-machi 4-1-1, Koganei-shi, Tokyo 184-8501, Japan. Electronic address: bio-mita@u-gakugei.ac.jp.
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Mita
authors.affiliation: Department of Biology, Faculty of Education, Tokyo Gakugei University, Nukuikita-machi 4-1-1, Koganei-shi, Tokyo 184-8501, Japan.
authors.forename: Misaki
authors.initials: M
authors.lastname: Daiya
authors.affiliation: Department of Biology, Faculty of Education, Tokyo Gakugei University, Nukuikita-machi 4-1-1, Koganei-shi, Tokyo 184-8501, Japan; Laboratory of Integrative Brain Sciences, Department of Biology and Center for Medical Life Science, Waseda University, Wakamatsucho 2-2, Shinjuku-ku, Tokyo 162-8480, Japan.
authors.forename: Shogo
authors.initials: S
authors.lastname: Haraguchi
authors.affiliation: Laboratory of Integrative Brain Sciences, Department of Biology and Center for Medical Life Science, Waseda University, Wakamatsucho 2-2, Shinjuku-ku, Tokyo 162-8480, Japan.
authors.forename: Kazuyoshi
authors.initials: K
authors.lastname: Tsutsui
authors.affiliation: Institute for Collaborative Relations, Ehime University, Matsuyama, Ehime 790-8577, Japan.
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Nagahama
mesh_terms: D000818:Animals; D005260:Female; D006066:Gonads / Q000378:metabolism*; D006801:Humans; D012065:Relaxin / Q000378:metabolism*; D013215:Starfish / Q000378:metabolism*
chemical_list: D012065:Relaxin
keywords: Coding-DNA sequence; Gamete spawning; Relaxin-like gonad-stimulating peptide; Species-specificity; Starfish Asterias amurensis