title: Characterization of GnRH-like peptides from the nerve ganglia of Yesso scallop, Patinopecten yessoensis.
abstract: There is yet no firm experimental evidence that the evolutionary ancient gonadotropin-releasing hormone GnRH (i.e., GnRH1) also acts in invertebrate gametogenesis. The objective of this paper is to characterize candidate invGnRH peptides of Yesso scallop Patinopecten yessoensis (i.e., peptide identification, immunohistochemical localization, and immunoquantification) in order to reveal their bioactive form in bivalves. Using mass spectrometry (MS), we identified two invGnRH (py-GnRH) peptides from the scallop nerve ganglia: a precursor form of py-GnRH peptide (a non-amidated dodecapeptide; py-GnRH12aa-OH) and a mature py-GnRH peptide (an amidated undecapeptide; py-GnRH11aa-NH2). Immunohistochemical staining allowed the localization of both py-GnRH peptides in the neuronal cell bodies and fibers of the cerebral and pedal ganglia (CPG) and the visceral ganglion (VG). We found that the peptides showed a dimorphic distribution pattern. Notably, the broad distribution of mature py-GnRH in neuronal fibers elongating to peripheral organs suggests that it is multi-functional. Time-resolved fluorescent immunoassays (TR-FIA) enabled the quantification of each py-GnRH form in the single CPG or VG tissue obtained from one individual. In addition, we observed greater abundance of mature py-GnRH in VG compared with its level in CPG, suggesting that VG is the main producing organ of mature py-GnRH peptide and that py-GnRH may play a central regulatory role in neurons of scallops. Our study provides evidence, for the first time, for the presence of precursor and mature forms of invGnRH peptides in the nerve ganglia of an invertebrate.
authors.affiliation: Laboratory of Aquacultural Biology, Graduate School of Agricultural Science, Tohoku University, 1-1 Amamiya-Machi, Tsutsumidori, Aoba-Ku, Sendai, Miyagi 981 8555, Japan.
authors.forename: Kazue
authors.initials: K
authors.lastname: Nagasawa
authors.affiliation: Suntory Institute for Bioorganic Research, 1-1-1 Wakayamadai, Shimamoto, Mishima, Osaka 618-8503, Japan.
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Osugi
authors.affiliation: Laboratory of Aquacultural Biology, Graduate School of Agricultural Science, Tohoku University, 1-1 Amamiya-Machi, Tsutsumidori, Aoba-Ku, Sendai, Miyagi 981 8555, Japan.
authors.forename: Iwao
authors.initials: I
authors.lastname: Suzuki
authors.affiliation: Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1, Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.
authors.forename: Naoki
authors.initials: N
authors.lastname: Itoh
authors.affiliation: Laboratory of Aquacultural Biology, Graduate School of Agricultural Science, Tohoku University, 1-1 Amamiya-Machi, Tsutsumidori, Aoba-Ku, Sendai, Miyagi 981 8555, Japan.
authors.forename: Keisuke G
authors.initials: KG
authors.lastname: Takahashi
authors.affiliation: Suntory Institute for Bioorganic Research, 1-1-1 Wakayamadai, Shimamoto, Mishima, Osaka 618-8503, Japan.
authors.forename: Honoo
authors.initials: H
authors.lastname: Satake
authors.affiliation: Laboratory of Aquacultural Biology, Graduate School of Agricultural Science, Tohoku University, 1-1 Amamiya-Machi, Tsutsumidori, Aoba-Ku, Sendai, Miyagi 981 8555, Japan. Electronic address: mosada@bios.tohoku.ac.jp.
authors.forename: Makoto
authors.initials: M
authors.lastname: Osada
mesh_terms: D000818:Animals; D017952:Ganglia, Invertebrate / Q000737:chemistry / Q000378:metabolism*; D007987:Gonadotropin-Releasing Hormone / Q000737:chemistry / Q000378:metabolism*; D009842:Oligopeptides / Q000737:chemistry / Q000378:metabolism*; D049897:Pectinidae / Q000737:chemistry / Q000378:metabolism*
chemical_list: D009842:Oligopeptides; D007987:Gonadotropin-Releasing Hormone
keywords: Bivalve; Cerebral and pedal ganglia; Mollusk; Neuropeptide; Visceral ganglion