title: Cloning and characterization of Xen-dorphin prohormone from Xenopus laevis: a new opioid-like prohormone distinct from proenkephalin and prodynorphin.
abstract: Opioid-like peptides mediate analgesia and induce behavioral effects such as tolerance and dependence by ligand-receptor-mediated mechanisms. The classical opioid prohormones can generate several bioactive peptides, and these divergent families of prohormones share a common well conserved ancestral opioid motif (Tyr-Gly-Gly-Phe). Evidence from pharmacological and molecular cloning studies indicates the presence of multiple isoforms of opioid ligands and receptors that are as yet uncharacterized. To identify potential new members we used the opioid motif as an anchor sequence and isolated two distinct isoforms (Xen-dorphins A and B) of an opioid prohormone from Xenopus laevis brain cDNA library. Xen-dorphin prohormones can generate multiple novel opioid ligands distinct from the known members of this family. Both isoforms are present in a wide variety of tissues including the brain. Two potential bioactive peptides, Xen-dorphin-1A and -1B, that were chemically synthesized showed opioid agonist activity in frog and rat brain membranes using a [35S]GTPgammaS assay. Initial radioligand binding experiments demonstrated that Xen-dorphin-1B binds with high affinity to opioid receptor(s) and with potential preference to the kappa-opioid receptor subtype. Cloning of the Xen-dorphin prohormone provides new evidence for the potential presence of other members in the opioid peptide superfamily.
authors.affiliation: Center for Biomarker Discovery, Department of Pediatrics, Oregon Health and Science University, Portland, Oregon 97239, USA.
authors.forename: Patrick
authors.initials: P
authors.lastname: Pattee
authors.forename: Alina-Elena
authors.initials: AE
authors.lastname: Ilie
authors.forename: Sandor
authors.initials: S
authors.lastname: Benyhe
authors.forename: Geza
authors.initials: G
authors.lastname: Toth
authors.forename: Anna
authors.initials: A
authors.lastname: Borsodi
authors.forename: Srinivasa R
authors.initials: SR
authors.lastname: Nagalla
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001921:Brain / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004745:Enkephalins / Q000737:chemistry / Q000235:genetics*; D015723:Gene Library; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000378:metabolism; D006728:Hormones / Q000378:metabolism; D007700:Kinetics; D008024:Ligands; D008969:Molecular Sequence Data; D036361:Peptide Hormones / Q000737:chemistry* / Q000235:genetics*; D020033:Protein Isoforms; D011498:Protein Precursors / Q000737:chemistry* / Q000235:genetics*; D051381:Rats; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid; D014018:Tissue Distribution; D014982:Xenopus laevis / Q000235:genetics* / Q000378:metabolism*
chemical_list: D018076:DNA, Complementary; D004745:Enkephalins; D006728:Hormones; D008024:Ligands; D036361:Peptide Hormones; D020033:Protein Isoforms; D011498:Protein Precursors; C481279:Xen-dorphin prohormone, Xenopus; C029992:proenkephalin; D016244:Guanosine 5'-O-(3-Thiotriphosphate); C033660:preproenkephalin