title: Primary structure, tissue distribution, and biological activity of chicken motilin receptor.
abstract: Motilin is a peptide hormone involved in gastrointestinal motility. GPR38, initially cloned as an orphan receptor, is now considered a specific receptor for motilin. Previously, molecular characterization of the motilin receptor had only been performed in mammalian and fish species. In this study, we cloned cDNA for chicken motilin receptor from the duodenum and characterized its primary structure, tissue distribution, and biological activity. The cDNA encoded 349 amino acids showing significant overall sequence identity to mammalian motilin receptors. Chicken motilin increased intracellular Ca2+ concentration in human embryonic kidney (HEK) 293 cells transiently expressing the recombinant chicken motilin receptor. Comparison of the cDNA sequence with the genomic sequence of chicken motilin receptor revealed that the chicken motilin receptor gene consists of two exons separated by an intron. Real-time PCR analysis showed that chicken motilin receptor mRNA is expressed in a wide range of tissues in 21-day-old chickens, with markedly high levels in the proventriculus, duodenum, and oviduct. The expression levels of the mRNA in the proventriculus and duodenum were highest just before hatching and rapidly decreased during post-hatch development. These results suggest that chicken motilin receptor is largely involved in gastrointestinal functions at pre- and post-hatch periods through an intracellular signaling pathway accompanied by an increase in Ca2+ levels.
authors.affiliation: High-Tech Research Center, Nippon Veterinary and Life Science University, Musashino, Tokyo 180-8602, Japan.
authors.forename: Ichiro
authors.initials: I
authors.lastname: Yamamoto
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Kaiya
authors.forename: Chihiro
authors.initials: C
authors.lastname: Tsutsui
authors.forename: Takafumi
authors.initials: T
authors.lastname: Sakai
authors.forename: Akira
authors.initials: A
authors.lastname: Tsukada
authors.forename: Mikiya
authors.initials: M
authors.lastname: Miyazato
authors.forename: Minoru
authors.initials: M
authors.lastname: Tanaka
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002642:Chick Embryo; D002645:Chickens / Q000502:physiology*; D018076:DNA, Complementary / Q000096:biosynthesis / Q000235:genetics; D004386:Duodenum / Q000378:metabolism; D005822:Genetic Vectors; D008969:Molecular Sequence Data; D011531:Proventriculus / Q000378:metabolism; D011964:Receptors, Gastrointestinal Hormone / Q000737:chemistry / Q000378:metabolism / Q000502:physiology*; D018013:Receptors, Neuropeptide / Q000737:chemistry / Q000378:metabolism / Q000502:physiology*; D014018:Tissue Distribution
chemical_list: D018076:DNA, Complementary; D011964:Receptors, Gastrointestinal Hormone; D018013:Receptors, Neuropeptide; C050802:motilin receptor