Identification, Localization, and Function of a Novel Avian Hypothalamic Neuropeptide, 26RFa, and Its Cognate Receptor, G Protein-Coupled Receptor-103

• Published in: Endocrinology (Philadelphia) 2010-05, Vol.151 (5), p.2255-2264
• Main Authors: Ukena, Kazuyoshi, Tachibana, Tetsuya, Iwakoshi-Ukena, Eiko, Saito, Yumiko, Minakata, Hiroyuki, Kawaguchi, Ryoko, Osugi, Tomohiro, Tobari, Yasuko, Leprince, Jérôme, Vaudry, Hubert, Tsutsui, Kazuyoshi
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Amino acids; Animals; Avian Proteins; Avian Proteins - genetics; Avian Proteins - metabolism; Avian Proteins - pharmacology; Biological and medical sciences; Brain; C-Terminus; Calcium; Calcium (intracellular); Calcium - metabolism; Calcium ions; Cell Behavior; Cell Line; Cellular Biology; Chemical Sciences; Chickens; Chickens - genetics; Chickens - metabolism; Chickens - physiology; Coding; Coturnix; Coturnix - genetics; Coturnix - metabolism; Diencephalon; DNA, Complementary; DNA, Complementary - chemistry; DNA, Complementary - genetics; Eating; Eating - drug effects; Feeding behavior; Fundamental and applied biological sciences. Psychology; Gene expression; Gene Expression Profiling; Glycine; Gonadotropins; Humans; Hypothalamic Hormones; Hypothalamic Hormones - genetics; Hypothalamic Hormones - metabolism; Hypothalamic Hormones - pharmacology; Hypothalamus; Hypothalamus - metabolism; Injections, Intraventricular; Intracerebroventricular administration; Life Sciences; Localization; Male; Mass spectrometry; Mass spectroscopy; Medicinal Chemistry; Molecular Sequence Data; mRNA; Neurobiology; Neurons and Cognition; Neuropeptides; Neuropeptides - genetics; Neuropeptides - metabolism; Neuropeptides - pharmacology; Peptides; Pharmaceutical sciences; Pharmacology; Pituitary (anterior); Precursors; Proteins; Receptors; Receptors, G-Protein-Coupled; Receptors, G-Protein-Coupled - genetics; Receptors, G-Protein-Coupled - metabolism; Reverse Transcriptase Polymerase Chain Reaction; Sequence Analysis, DNA; Sequence Homology, Amino Acid; Vertebrates; Vertebrates: endocrinology
• ISSN: 0013-7227; 1945-7170
• DOI: 10.1210/en.2009-1478

Several neuropeptides with the C-terminal RFamide sequence have been identified in the hypothalamus of a variety of vertebrates. Among the RFamide peptide groups, however, only LPXRFamide peptides, including gonadotropin-inhibitory hormone, have been characterized in the avian brain. In the present study, we sought for the presence of other RFamide peptides in the avian hypothalamus. We identified a cDNA encoding an RFamide peptide orthologous to 26RFa (also referred to as QRFP) in the hypothalamus of the Japanese quail. The deduced quail 26RFa precursor consisted of 120-amino-acid residues, encoding one RFamide peptide with 27 amino acids. This RFamide peptide was flanked at the N terminus by a dibasic amino acid cleavage site and at the C terminus by a glycine amidation signal. Quantitative RT-PCR analysis demonstrated specific expression of quail 26RFa mRNA in the diencephalon including the hypothalamus. Furthermore, mass spectrometry analysis revealed the presence of a peptide exhibiting the mass of mature 26RFa, indicating that the peptide is actually produced from the precursor in the diencephalon. 26RFa-producing cell bodies were localized in the anterior hypothalamic nucleus in the brain. Synthetic 26RFa increased intracellular Ca2+ concentration in HEK293T cells transfected with the chicken G protein-coupled receptor GPR103. Intracerebroventricular injection of 26RFa in broiler chicks stimulated feeding behavior. These data provide the first evidence for the occurrence of the peptide 26RFa in the avian hypothalamus and indicate that this peptide exerts orexigenic activity. A novel neuropeptide, 26RFa, and its cognate receptor, GPR103, involved in orexigenic activity in birds have been found.