title: Molecular identification of uncoupling proteins (UCP2 and UCP3) and absence of UCP1 in the marsupial Tasmanian bettong, Bettongia gaimardi.
abstract: This study has identified the expression of uncoupling proteins in a marsupial using molecular techniques. The Tasmanian bettong, Bettongia gaimardi, increases non-shivering thermogenesis (NST) in response to cold exposure and norepinephrine, although previous studies have been unable to demonstrate the presence of brown adipose tissue or uncoupling protein 1 (UCP1). This study used molecular techniques to confirm the absence of UCP1 as well as ascertain if this species expresses UCP2 and/or UCP3. Tissue samples from four B. gaimardi were taken prior to and post-cold exposure at 4-5 degrees C for 2 weeks. The tissues were then examined for UCP1, UCP2 and UCP3 expression using Western blotting. UCP2 and UCP3 were amplified through RT-PCR and subsequently sequenced to confirm molecular identity. Our work confirms that B. gaimardi does not express UCP1 and that this species expresses both uncoupling proteins 2 and 3. The sequencing of the amplified B. gaimardi UCP2 and UCP3 cDNAs have revealed a 74% homology with rat UCP2 cDNA, and 65% homology with rat UCP3 cDNA. Although this work has not yet characterised the functional properties of these proteins in the marsupial, it does suggest a possible mechanism to explain the existence of NST in B. gaimardi.
authors.affiliation: School of Zoology, University of Tasmania, G.P.O. Box 252-05, Sandy Bay, Hobart, Tasmania 7005, Australia. alexander.kabat@utas.edu.au
authors.forename: Alexander P
authors.initials: AP
authors.lastname: Kabat
authors.forename: Randy W
authors.initials: RW
authors.lastname: Rose
authors.forename: Julie
authors.initials: J
authors.lastname: Harris
authors.forename: Adrian K
authors.initials: AK
authors.lastname: West
mesh_terms: D002001:Adipose Tissue, Brown / Q000378:metabolism; D000818:Animals; D015153:Blotting, Western; D002352:Carrier Proteins / Q000096:biosynthesis / Q000235:genetics*; D018076:DNA, Complementary / Q000378:metabolism; D007473:Ion Channels; D008297:Male; D008394:Marsupialia; D008565:Membrane Proteins / Q000096:biosynthesis / Q000235:genetics*; D026901:Membrane Transport Proteins; D024101:Mitochondrial Proteins; D014176:Protein Biosynthesis; D011506:Proteins / Q000235:genetics*; D051381:Rats; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013696:Temperature; D014018:Tissue Distribution; D000071256:Uncoupling Protein 1; D000071246:Uncoupling Protein 2; D000071247:Uncoupling Protein 3
chemical_list: D002352:Carrier Proteins; D018076:DNA, Complementary; D007473:Ion Channels; D008565:Membrane Proteins; D026901:Membrane Transport Proteins; D024101:Mitochondrial Proteins; D011506:Proteins; C000604373:Ucp1 protein, rat; C000604391:Ucp2 protein, rat; C000604394:Ucp3 protein, rat; D000071256:Uncoupling Protein 1; D000071246:Uncoupling Protein 2; D000071247:Uncoupling Protein 3