title: Characterization of chicken secretin (SCT) and secretin receptor (SCTR) genes: a novel secretin-like peptide (SCT-LP) and secretin encoded in a single gene.
abstract: Secretin and the secretin receptor have been reported to play an important role in regulating pancreatic water and bicarbonate secretion in mammals; however, little is known about their expression, structure, and biological functions in non-mammalian vertebrates including birds. In this study, the full-length cDNAs encoding secretin and secretin receptor have first been cloned from duodenum of adult chickens. The putative chicken secretin receptor (cSCTR) is 449 amino acids in length and shares high sequence identity (58-63%) with its mammalian counterparts. Interestingly, chicken secretin cDNA encodes not only the secretin peptide (cSCT), but also a novel secretin-like peptide (cSCT-LP), which shares high amino acid identity with chicken (56%) and mammalian (48-52%) secretin. Using a pGL3-CRE-luciferase reporter system, we further demonstrated that both cSCT (EC(50): 0.31nM) and cSCT-LP (EC(50): 1.10nM), but not other structurally-related peptides, could potently activate cSCTR expressed in CHO cells, suggesting that both peptides may function as potential ligands for cSCTR. Using RT-PCR, the expression of secretin and secretin receptor in adult chicken tissues was also examined. Secretin was detected to be predominantly expressed in small intestine, while the mRNA expression of cSCTR was restricted to several tissues including gastrointestinal tract, liver, testis, pancreas and several brain regions. Collectively, results from present study not only established a molecular basis to elucidate the physiological roles of SCT, SCT-LP and SCTR in chickens, but also provide critical insights into structural and functional changes of secretin and its receptor during vertebrate evolution.
authors.affiliation: Key Laboratory of Bio-resources and Eco-environment of Ministry of Education, School of Life Sciences, Sichuan University, Chengdu 610064, PR China. cdwyjhk@gmail.com
authors.forename: Yajun
authors.initials: Y
authors.lastname: Wang
authors.forename: Guian
authors.initials: G
authors.lastname: Huang
authors.forename: Juan
authors.initials: J
authors.lastname: Li
authors.forename: Fengyan
authors.initials: F
authors.lastname: Meng
authors.forename: Xiaping
authors.initials: X
authors.lastname: He
authors.forename: Frederick C
authors.initials: FC
authors.lastname: Leung
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D016466:CHO Cells; D002645:Chickens; D003001:Cloning, Molecular; D006224:Cricetinae; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D019143:Evolution, Molecular; D005091:Exons; D005768:Gastrointestinal Hormones / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology; D017930:Genes, Reporter; D008156:Luciferases / Q000096:biosynthesis / Q000235:genetics; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000378:metabolism; D043562:Receptors, G-Protein-Coupled / Q000235:genetics* / Q000378:metabolism; D011964:Receptors, Gastrointestinal Hormone / Q000235:genetics* / Q000378:metabolism; D012633:Secretin / Q000235:genetics* / Q000378:metabolism / Q000494:pharmacology; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction; D014018:Tissue Distribution
chemical_list: D005768:Gastrointestinal Hormones; D012333:RNA, Messenger; D043562:Receptors, G-Protein-Coupled; D011964:Receptors, Gastrointestinal Hormone; C029937:secretin receptor; D012633:Secretin; D008156:Luciferases; D017868:Cyclic AMP-Dependent Protein Kinases