Isolation, cloning, and tissue expression of a putative octopamine/tyramine receptor from locust visceral muscle tissues

Abstract

Octopamine has been shown to play major roles in invertebrate nervous systems as a neurotransmitter, neuromodulator, and neurohormone. Tyramine is the biochemical precursor of octopamine and its neuromodulatory role is now being investigated and clarified in invertebrates, particularly in insects. Both octopamine and tyramine mediate their actions via G protein-coupled receptors (GPCRs) and are believed to play important functions in the regulation of physiological processes in locust oviduct. Here we report the isolation, cloning, and tissue expression of a putative octopamine/tyramine receptor from the locust, Locusta migratoria. Degenerate oligonucleotides in PCR reactions were first used to obtain partial cDNA sequences and then these partial sequences were used in screens to obtain a full-length cDNA. The cloned cDNA is about 3.1 kb long and encodes a protein of 484 amino acid residues with typical characteristics of GPCRs including seven transmembrane domains and many signature residues. The amino acid sequence of the cloned cDNA displays sequence similarities with known GPCRs, particularly octopamine/tyramine receptors. Screening of the locust genomic DNA library resulted in isolation of a genomic DNA with the same size as the cDNA, indicating that the gene is intron-less. RT-PCR and Northern blot analyses revealed the expression of the receptor mRNA in brain, ventral nerve cord, oviduct, and midgut tissues. Southern blot analyses using EcoRI and HindIII restriction endonucleases recognized at least two distinct gene bands.

Octopamine Receptors from the Barnacle Balanus improvisus Are Activated by the α2-Adrenoceptor Agonist Medetomidine

“…Two different primer pairs were chosen that had previously enabled cloning of an Oct/Tyr receptor from the grasshopper Locusta migratoria and a serotonin receptor from the nematode Haemonchus contortus (Smith et al, 2003;Molaei et al, 2005). Twenty-nine clones were isolated using the first primer pair.…”

Trace amine-associated receptor 1—Family archetype or iconoclast?

“…In addition to providing the means by which to further characterize Drosophila OCT/TYR GPCRs these clones served as nucleic acid hybridization probes that were used to identify and isolate homologous receptor sequences from several invertebrate species (Vanden Broeck et al, 1995;von Nickisch-Rosenegk et al, 1996;Gerhardt et al, 1997a;Gerhardt et al, 1997b;Reale et al, 1997;Baxter & Barker, 1999;Blenau et al 2000;Chang et al, 2000;Poels et al, 2001;Rex & Komuniecki, 2002;Ohta et al, 2003;Farooqui et al, 2003;Farooqui et al, 2004;Grohmann et al, 2003;Bischof & Enan, 2004;Balfanz, 2005;Molaei et al, 2005;Mustard et al 2005;Rex et al, 2005;Dacks et al, 2006). These clones have also been instrumental in identifying the important structural features that particpate in the binding of ligand and coupling of the the receptor to its effectors (Chatwin et al, 2003;Huang, 2003;Ohta et al, 2004).…”

Octopamine and tyramine regulate the activity of reproductive visceral muscles in the adult female blood-feeding bug, Rhodnius prolixus

“…Also, octopamine has been shown to decrease the amplitude of proctolin-induced contractions in a dosedependent manner Nykamp and Lange, 2000). These effects appear to be mediated by an Oct/Tyr receptor shown to be expressed in the oviducts of locusts (Molaei et al, 2005). In Drosophila and the stable fly Stomoxys calcitrans, octopamine reduces the amplitude and frequency of contractions, and reduces basal tonus of the oviducts in a dose-dependent manner (Cook and Wagner, 1992;Middleton et al, 2006;Rodríguez-Valentín et al, 2006).…”