File Download
  Links for fulltext
     (May Require Subscription)
Supplementary

postgraduate thesis: Molecular characterization of chicken galanin and galanin receptor family

TitleMolecular characterization of chicken galanin and galanin receptor family
Authors
Issue Date2011
PublisherThe University of Hong Kong (Pokfulam, Hong Kong)
Citation
Ho, C. J. [何志泓]. (2011). Molecular characterization of chicken galanin and galanin receptor family. (Thesis). University of Hong Kong, Pokfulam, Hong Kong SAR. Retrieved from http://dx.doi.org/10.5353/th_b4775264
Abstract Galanin is a multi-functional neuropeptide with widespread distribution in the central and peripheral nervous systems of different species. It exerts a broad spectrum of physiological functions through the interactions with three galanin receptor subtypes namely the GalR1, GalR2 and GalR3, which have only been identified in mammals. In contrast to the extensive studies in mammals, little is known about the structures and functions of galanin and its receptors in avian species. In the present study, a total of nine chicken cDNAs including four galanin prepropeptide transcript variants (cGal -v1 to -v4), the three known galanin receptor subtypes (cGalR1, cGalR2 and cGalR3), and two novel galanin receptor subtypes designated the GalR1-like (cGalR1-L) and GalR2-like (cGalR2-L), were cloned from the brain and intestine tissues, respectively. The four cGal transcript variants encode precursor peptides of 117, 141, 88 and 150 residues, respectively, which eventually produce two isoforms of mature chicken galanin peptide, the cGal (1-29) and a novel cGal (1-53), through proteolytic processing of the galanin prepropeptide. The five isolated cGalR cDNAs encode receptor proteins of 357-to 405-residue-long, which share amino acid sequence identities ranged from 50% to 86% with their corresponding mammalian counterparts. From RT-PCR analysis, the cGal and cGalRs (except for cGalR3) showed diverse mRNA expression profiles among the adult chicken tissues examined including different regions of the oviduct. Using luciferase reporter systems, it was demonstrated that all the five cGalRs, transiently transfected in Chinese hamster ovary (CHO) cells, were functionally and differentially coupled to Gs, Gi or Gq protein signalling pathways upon the activations of chicken galanin peptides cGal (1-29), cGal (1-53) and human galanin-like peptide hGALP (1-60), with distinct potencies. The newly identified cGalR1-L and cGalR2-L share similarities with cGalR1 and cGalR2, respectively, in terms of the sequence homology, exon/intron organization and signalling pathways, thus suggesting an early gene duplication event in vertebrate evolution in the galanin receptor family. On the other hand, the failure of identifying GalR1-L and GalR2-L genes in mammalian species suggests their deletion events in the mammalian lineage, which are supported by the comparative synteny analyses of galanin receptor family between the human, chicken, zebrafish and Xenopus genomes. Together, these findings establish a molecular basis to elucidate the physiological roles of galanin and its receptors in birds.
DegreeMaster of Philosophy
SubjectNeuropeptides.
Neuropeptides - Receptors.
Chickens - Genetics.
Dept/ProgramBiological Sciences
Persistent Identifierhttp://hdl.handle.net/10722/181474

 

DC FieldValueLanguage
dc.contributor.authorHo, Chi-wang, John.-
dc.contributor.author何志泓.-
dc.date.accessioned2013-03-03T03:19:48Z-
dc.date.available2013-03-03T03:19:48Z-
dc.date.issued2011-
dc.identifier.citationHo, C. J. [何志泓]. (2011). Molecular characterization of chicken galanin and galanin receptor family. (Thesis). University of Hong Kong, Pokfulam, Hong Kong SAR. Retrieved from http://dx.doi.org/10.5353/th_b4775264-
dc.identifier.urihttp://hdl.handle.net/10722/181474-
dc.description.abstract Galanin is a multi-functional neuropeptide with widespread distribution in the central and peripheral nervous systems of different species. It exerts a broad spectrum of physiological functions through the interactions with three galanin receptor subtypes namely the GalR1, GalR2 and GalR3, which have only been identified in mammals. In contrast to the extensive studies in mammals, little is known about the structures and functions of galanin and its receptors in avian species. In the present study, a total of nine chicken cDNAs including four galanin prepropeptide transcript variants (cGal -v1 to -v4), the three known galanin receptor subtypes (cGalR1, cGalR2 and cGalR3), and two novel galanin receptor subtypes designated the GalR1-like (cGalR1-L) and GalR2-like (cGalR2-L), were cloned from the brain and intestine tissues, respectively. The four cGal transcript variants encode precursor peptides of 117, 141, 88 and 150 residues, respectively, which eventually produce two isoforms of mature chicken galanin peptide, the cGal (1-29) and a novel cGal (1-53), through proteolytic processing of the galanin prepropeptide. The five isolated cGalR cDNAs encode receptor proteins of 357-to 405-residue-long, which share amino acid sequence identities ranged from 50% to 86% with their corresponding mammalian counterparts. From RT-PCR analysis, the cGal and cGalRs (except for cGalR3) showed diverse mRNA expression profiles among the adult chicken tissues examined including different regions of the oviduct. Using luciferase reporter systems, it was demonstrated that all the five cGalRs, transiently transfected in Chinese hamster ovary (CHO) cells, were functionally and differentially coupled to Gs, Gi or Gq protein signalling pathways upon the activations of chicken galanin peptides cGal (1-29), cGal (1-53) and human galanin-like peptide hGALP (1-60), with distinct potencies. The newly identified cGalR1-L and cGalR2-L share similarities with cGalR1 and cGalR2, respectively, in terms of the sequence homology, exon/intron organization and signalling pathways, thus suggesting an early gene duplication event in vertebrate evolution in the galanin receptor family. On the other hand, the failure of identifying GalR1-L and GalR2-L genes in mammalian species suggests their deletion events in the mammalian lineage, which are supported by the comparative synteny analyses of galanin receptor family between the human, chicken, zebrafish and Xenopus genomes. Together, these findings establish a molecular basis to elucidate the physiological roles of galanin and its receptors in birds.-
dc.languageeng-
dc.publisherThe University of Hong Kong (Pokfulam, Hong Kong)-
dc.relation.ispartofHKU Theses Online (HKUTO)-
dc.rightsThe author retains all proprietary rights, (such as patent rights) and the right to use in future works.-
dc.rightsCreative Commons: Attribution 3.0 Hong Kong License-
dc.source.urihttp://hub.hku.hk/bib/B47752646-
dc.subject.lcshNeuropeptides.-
dc.subject.lcshNeuropeptides - Receptors.-
dc.subject.lcshChickens - Genetics.-
dc.titleMolecular characterization of chicken galanin and galanin receptor family-
dc.typePG_Thesis-
dc.identifier.hkulb4775264-
dc.description.thesisnameMaster of Philosophy-
dc.description.thesislevelMaster-
dc.description.thesisdisciplineBiological Sciences-
dc.description.naturepublished_or_final_version-
dc.identifier.doi10.5353/th_b4775264-
dc.date.hkucongregation2012-

Export via OAI-PMH Interface in XML Formats


OR


Export to Other Non-XML Formats