title: RFamide peptides in agnathans and basal chordates.
abstract: Since a peptide with a C-terminal Arg-Phe-NH2 (RFamide peptide) was first identified in the ganglia of the venus clam in 1977, RFamide peptides have been found in the nervous system of both invertebrates and vertebrates. In vertebrates, the RFamide peptide family includes gonadotropin-inhibitory hormone (GnIH), neuropeptide FF (NPFF), prolactin-releasing peptide (PrRP), pyroglutamylated RFamide peptide/26RFamide peptide (QRFP/26RFa), and kisspeptins (kiss1 and kiss2). They are involved in important functions such as the release of hormones, regulation of sexual or social behavior, pain transmission, reproduction, and feeding. In contrast to tetrapods and jawed fish, the information available on RFamide peptides in agnathans and basal chordates is limited, thus preventing further insights into the evolution of RFamide peptides in vertebrates. In this review, we focus on the previous research and recent advances in the studies on RFamide peptides in agnathans and basal chordates. In agnathans, the genes encoding GnIH, NPFF, and PrRP precursors and the mature peptides have been identified in lamprey (Petromyzon marinus) and hagfish (Paramyxine atami). Putative kiss1 and kiss2 genes have also been found in the genome database of lamprey. In basal chordates, namely, in amphioxus (Branchiostoma japonicum), a common ancestral form of GnIH and NPFF genes and their mature peptides, as well as the ortholog of the QRFP gene have been identified. The studies revealed that the number of orthologs of vertebrate RFamide peptides present in agnathans and basal chordates is greater than expected, suggesting that the vertebrate RFamide peptides might have emerged and expanded at an early stage of chordate evolution.
authors.affiliation: Bioorganic Research Institute, Suntory Foundation for Life Sciences, 1-1-1 Wakayamadai, Shimamoto, Mishima, Osaka 618-8503, Japan. Electronic address: osugi@sunbor.or.jp.
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Osugi
authors.affiliation: Department of Biology and Center for Medical Life Science, Waseda University, Shinjuku, Tokyo 162-8480, Japan.
authors.forename: You Lee
authors.initials: YL
authors.lastname: Son
authors.affiliation: Department of Biology and Center for Medical Life Science, Waseda University, Shinjuku, Tokyo 162-8480, Japan.
authors.forename: Takayoshi
authors.initials: T
authors.lastname: Ubuka
authors.affiliation: Bioorganic Research Institute, Suntory Foundation for Life Sciences, 1-1-1 Wakayamadai, Shimamoto, Mishima, Osaka 618-8503, Japan.
authors.forename: Honoo
authors.initials: H
authors.lastname: Satake
authors.affiliation: Department of Biology and Center for Medical Life Science, Waseda University, Shinjuku, Tokyo 162-8480, Japan.
authors.forename: Kazuyoshi
authors.initials: K
authors.lastname: Tsutsui
mesh_terms: D000818:Animals; D005075:Biological Evolution; D006196:Hagfishes / Q000235:genetics / Q000378:metabolism*; D059648:Kisspeptins / Q000235:genetics / Q000378:metabolism*; D064175:Lancelets / Q000235:genetics / Q000378:metabolism*; D009479:Neuropeptides / Q000235:genetics / Q000378:metabolism*; D009842:Oligopeptides / Q000235:genetics / Q000378:metabolism; D048428:Petromyzon / Q000235:genetics / Q000378:metabolism*; D056690:Prolactin-Releasing Hormone / Q000235:genetics / Q000378:metabolism
chemical_list: D059648:Kisspeptins; D009479:Neuropeptides; D009842:Oligopeptides; D056690:Prolactin-Releasing Hormone; C416987:RFamide peptide; C053651:phenylalanyl-leucyl-phenylalanyl-glutaminyl-prolyl-glutaminyl-arginyl-phenylalaninamide
keywords: Agnathan; Chordate; Gonadotropin-inhibitory hormone (GnIH); Molecular evolution; RFamide peptides