title: Organization of two independent kisspeptin systems derived from evolutionary-ancient kiss genes in the brain of zebrafish.
abstract: Kisspeptins are new actors in the neuroendocrine regulation of reproduction. In vertebrates, the number of kiss genes varies from none to three. Zebrafish have two kiss genes, kiss1 and kiss2, and two kiss receptors (GPR54), kiss1r and kiss2r. To provide detailed information on the organization of the kiss systems in zebrafish, antibodies were raised against the C terminus of zebrafish preproKiss1 and preproKiss2. Immunohistochemistry fully confirmed in situ hybridization data, showing that kiss1-expressing neurons are only located in the habenular nucleus, while kiss2-expressing neurons are found in the dorsal and ventral hypothalamus. Kiss1-expressing cells project only to the interpeduncular and raphe nuclei and strongly expressed the kiss1r receptor. In contrast, kiss2-expressing cells are mostly present in the dorsal and ventral hypothalamus and project widely into the subpallium, the preoptic area, the thalamus, the ventral and caudal hypothalamus, and the mesencephalon. All these regions strongly expressed the kiss2r messengers. Kiss2 fibers profusely innervate the ventral forebrain and notably made close apposition with GnRH3 neurons. Estrogen treatment of juvenile fish with estradiol causes increase in kiss2 and kiss2r expression. In the pituitary gland, no proKiss2- positive fibers were detected, while positive cells were observed in the pars intermedia. In addition to proposing a successful strategy to develop antibodies to kisspeptins, these data indicate that the kiss2 systems of zebrafish are implicated in reproductive events, while the kiss1 gene would play other functions that remain to be established.
authors.affiliation: Neurogenesis And Œstrogens, Unité Mixte de Recherche Centre National de la Recherche Scientifique 6026, Institut Fédératif de Recherche 140, Campus de Beaulieu, 35042 Rennes cedex, France.
authors.forename: Arianna
authors.initials: A
authors.lastname: Servili
authors.forename: Yann
authors.initials: Y
authors.lastname: Le Page
authors.forename: Jérôme
authors.initials: J
authors.lastname: Leprince
authors.forename: Alain
authors.initials: A
authors.lastname: Caraty
authors.forename: Sebastian
authors.initials: S
authors.lastname: Escobar
authors.forename: Ishwar S
authors.initials: IS
authors.lastname: Parhar
authors.forename: Jae Yong
authors.initials: JY
authors.lastname: Seong
authors.forename: Hubert
authors.initials: H
authors.lastname: Vaudry
authors.forename: Olivier
authors.initials: O
authors.lastname: Kah
mesh_terms: D000818:Animals; D001921:Brain / Q000187:drug effects / Q000378:metabolism*; D004967:Estrogens / Q000494:pharmacology; D019143:Evolution, Molecular; D007987:Gonadotropin-Releasing Hormone / Q000187:drug effects / Q000378:metabolism; D019262:Habenula / Q000187:drug effects / Q000378:metabolism; D007031:Hypothalamus / Q000187:drug effects / Q000378:metabolism; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D059648:Kisspeptins; D010902:Pituitary Gland / Q000187:drug effects / Q000378:metabolism; D016133:Polymerase Chain Reaction; D011761:Pyrrolidonecarboxylic Acid / Q000031:analogs & derivatives / Q000378:metabolism; D011903:Raphe Nuclei / Q000187:drug effects / Q000378:metabolism; D043562:Receptors, G-Protein-Coupled / Q000378:metabolism*; D000074502:Receptors, Kisspeptin-1; D025521:Tumor Suppressor Proteins / Q000378:metabolism*; D015027:Zebrafish; D029961:Zebrafish Proteins / Q000378:metabolism*
chemical_list: D004967:Estrogens; C527845:Kiss1 protein, zebrafish; D059648:Kisspeptins; D043562:Receptors, G-Protein-Coupled; D000074502:Receptors, Kisspeptin-1; D025521:Tumor Suppressor Proteins; D029961:Zebrafish Proteins; C448022:gonadotropin-releasing hormone-III; C527848:kiss1ra protein, zebrafish; D007987:Gonadotropin-Releasing Hormone; D011761:Pyrrolidonecarboxylic Acid