title: A relaxin-like gonad-stimulating peptide from the starfish Aphelasterias japonica.
abstract: Relaxin-like gonad-stimulating peptide (RGP) in starfish is the first identified invertebrate gonadotropin responsible for final gamete maturation. In this study, a new ortholog RGP was identified from Aphelasterias japonica. The DNA sequence encoding A. japonica RGP (AjaRGP) consists of 342 base pairs with an open reading frame encoding a peptide of 113 amino acids (aa), including a signal peptide (26aa), B-chain (20aa), C-peptide (42aa), and A-chain (25aa). AjaRGP is a heterodimeric peptide with disulfide cross-linkages. Comparing with Asterias amurensis RGP (AamRGP) and Patiria (=Asterina) pectinifera RGP (PpeRGP), the amino acid identity levels of AjaRGP with respect to AamRGP and PpeRGP are 84% and 58% for the A-chain and 90% and 68% for the B-chain, respectively. This suggests that AjaRGP is closer to AmaRGP rather than PpeRGP. Although chemical synthetic AjaRGP can induce gamete spawning and oocyte maturation in ovarian fragments of A. japonica, the ovary of P. pectinifera fails to respond to AjaRGP. This suggests that AjaRGP acts species-specifically.
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 Applied Biochemistry, School of Engineering, Tokai University, 4-1-1, Kitakaname, Hiratuska, Kanagawa 259-1292, Japan.
authors.forename: Hidekazu
authors.initials: H
authors.lastname: Katayama
mesh_terms: D000818:Animals; D005260:Female; D007447:Invertebrate Hormones / Q000235:genetics / Q000378:metabolism*; D012065:Relaxin / Q000378:metabolism*; D013215:Starfish / Q000235:genetics / Q000378:metabolism*
chemical_list: D007447:Invertebrate Hormones; D012065:Relaxin
keywords: Coding-DNA sequence; Gamete spawning; Relaxin-like gonad-stimulating peptide; Species-specificity; Starfish Aphelasterias japonica