Identification of 26RFa, a hypothalamic neuropeptide of the RFamide peptide family with orexigenic activity

doi:10.1073/pnas.2434676100

Identification of 26RFa, a hypothalamic neuropeptide of the RFamide peptide family with orexigenic activity

^*European Institute for Peptide Research (IFRMP23), Laboratory of Cellular and Molecular Neuroendocrinology, Institut National de la Santé et de la Recherche Médicale, U 413, University of Rouen, 76821 Mont-Saint-Aignan, France; ^†Laboratory of Neuroendocrinology and Immunological Biotechnology, Katholieke Universiteit Leuven, B-3000 Leuven, Belgium; ^‡European Institute for Peptide Research (IFRMP23), Centre National de la Recherche Scientifique, Unité Mixte de Recherche 6036, Laboratory of Experimental Neuropsychopharmacology, University of Rouen, 76183 Rouen, France; ^§Institut National de la Santé et de la Recherche Médicale, U 36, Collège de France, 75005 Paris, France; and ^¶Federative Research Institute 22, Laboratory of Neuroendocrinology and Neuronal Physiopathology, Institut National de la Santé et de la Recherche Médicale, U 422, 59045 Lille, France

Edited by Tomas Hökfelt, Karolinska Institute, Stockholm, Sweden (received for review July 24, 2003)

Abstract

A neuropeptide was isolated from a frog brain extract by HPLC purification and characterized by mass spectrometry. This 26-aa neuropeptide, which belongs to the RFamide peptide family, was designated 26RFa, and its primary structure was established as VGTALGSLAEELNGYNRKKGGFSFRF-NH₂. Research in databases revealed the presence of sequences homologous to frog 26RFa in the human genome and in rat ESTs. On the basis of this sequence information, the cDNAs encoding the human and rat 26RFa precursors were cloned. The two preproteins show a similar organization, with the 26RFa sequence located in the C-terminal region of the precursor. Human preprotein (prepro)-26RFa encodes an additional putative RFamide peptide that is not found in the rat precursor. The primary structures of human, rat, and frog 26RFa exhibit ≈80% identity, and the C-terminal octapeptide has been fully conserved from amphibians to mammals. In situ hybridization histochemistry revealed that, in the rat brain, the 26RFa gene is exclusively expressed in the ventromedial hypothalamic nucleus and in the lateral hypothalamic area. 26RFa induced a dose-dependent stimulation in cAMP production by rat pituitary cells in vitro and markedly increased food intake in mice. The conservation of the primary structure of 26RFa during vertebrate evolution, the discrete localization of the mRNA encoding its precursor in hypothalamic nuclei involved in the control of feeding behavior, and the observation that 26RFa possesses orexigenic properties indicate that this neuropeptide may play important biological functions.

Footnotes

↵ ∥ To whom correspondence should be addressed. E-mail: hubert.vaudry{at}univ-rouen.fr.
This paper was submitted directly (Track II) to the PNAS office.
Abbreviations: GnIH, gonadotropin-inhibiting hormone; LH, lateral hypothalamic area; NPFF, neuropeptide FF; NPFF-LI, NPFF-like immunoreactivity; PrRP, prolactin-releasing peptide; RFRP, FMRFamide-related peptide; R-RFa, Rana RFamide; VMH, ventromedial hypothalamic nucleus; prepro, preprotein.
Data deposition: The sequences reported in this paper have been deposited in the SWISS-PROT/TrEMBL database [accession no. P83683 (frog 26RFa)], and in the GenBank database [accession nos. AY438326 (human prepro-26RFa) and AY438327 (rat prepro-26RFa)].