title: Brown fat in a protoendothermic mammal fuels eutherian evolution.
abstract: Endothermy has facilitated mammalian species radiation, but the sequence of events leading to sustained thermogenesis is debated in multiple evolutionary models. Here we study the Lesser hedgehog tenrec (Echinops telfairi), a phylogenetically ancient, 'protoendothermic' eutherian mammal, in which constantly high body temperatures are reported only during reproduction. Evidence for nonshivering thermogenesis is found in vivo during periodic ectothermic-endothermic transitions. Anatomical studies reveal large brown fat-like structures in the proximity of the reproductive organs, suggesting physiological significance for parental care. Biochemical analysis demonstrates high mitochondrial proton leak catalysed by an uncoupling protein 1 ortholog. Strikingly, bioenergetic profiling of tenrec uncoupling protein 1 reveals similar thermogenic potency as modern mouse uncoupling protein 1, despite the large phylogenetic distance. The discovery of functional brown adipose tissue in this 'protoendothermic' mammal links nonshivering thermogenesis directly to the roots of eutherian evolution, suggesting physiological importance prior to sustained body temperatures and migration to the cold.
authors.affiliation: Department of Animal Physiology, Faculty of Biology, Philipps-Universität, Karl-von-Frisch Strasse 8, Marburg, Germany.
authors.forename: Rebecca
authors.initials: R
authors.lastname: Oelkrug
authors.forename: Nadja
authors.initials: N
authors.lastname: Goetze
authors.forename: Cornelia
authors.initials: C
authors.lastname: Exner
authors.forename: Yang
authors.initials: Y
authors.lastname: Lee
authors.forename: Goutham K
authors.initials: GK
authors.lastname: Ganjam
authors.forename: Maria
authors.initials: M
authors.lastname: Kutschke
authors.forename: Saskia
authors.initials: S
authors.lastname: Müller
authors.forename: Sigrid
authors.initials: S
authors.lastname: Stöhr
authors.forename: Matthias H
authors.initials: MH
authors.lastname: Tschöp
authors.forename: Paul G
authors.initials: PG
authors.lastname: Crichton
authors.forename: Gerhard
authors.initials: G
authors.lastname: Heldmaier
authors.forename: Martin
authors.initials: M
authors.lastname: Jastroch
authors.forename: Carola W
authors.initials: CW
authors.lastname: Meyer
mesh_terms: D000222:Adaptation, Physiological; D002001:Adipose Tissue, Brown / Q000502:physiology*; D000818:Animals; D005075:Biological Evolution; D001831:Body Temperature / Q000502:physiology; D007312:Eulipotyphla / Q000502:physiology*; D005260:Female; D015870:Gene Expression; D057809:HEK293 Cells; D006801:Humans; D007473:Ion Channels / Q000235:genetics / Q000378:metabolism*; D008297:Male; D051379:Mice; D008928:Mitochondria / Q000378:metabolism*; D024101:Mitochondrial Proteins / Q000235:genetics / Q000378:metabolism*; D010802:Phylogeny; D012098:Reproduction / Q000502:physiology*; D022722:Thermogenesis / Q000502:physiology*; D000071256:Uncoupling Protein 1
chemical_list: D007473:Ion Channels; D024101:Mitochondrial Proteins; C000604371:UCP1 protein, human; C000604372:Ucp1 protein, mouse; D000071256:Uncoupling Protein 1