title: Functional analysis of a mammalian odorant receptor subfamily.
abstract: Phylogenetic analysis groups mammalian odorant receptors into two broad classes and numerous subfamilies. These subfamilies are proposed to reflect functional organization. Testing this idea requires an assay allowing detailed functional characterization of odorant receptors. Here we show that a variety of Class I and Class II mouse odorant receptors can be functionally expressed in Xenopus laevis oocytes. Receptor constructs included the N-terminal 20 residues of human rhodopsin and were co-expressed with Galphaolf and the cystic fibrosis transmembrane regulator to allow electrophysiological measurement of receptor responses. For most mouse odorant receptors tested, these conditions were sufficient for functional expression. Co-expression of accessory proteins was required to allow functional surface expression of some mouse odorant receptors. We used this assay to examine the receptive ranges of all members of the mouse odorant receptor 42 (MOR42) subfamily. MOR42-1 responded to dicarboxylic acids, preferring a 10-12 carbon chain length. MOR42-2 responded to monocarboxylic acids (7-10 carbons). MOR42-3 responded to dicarboxylic acids (8-10 carbons) and monocarboxylic acids (10-12 carbons). Thus, the receptive range of each receptor was unique. However, overlap between the individual receptive ranges suggests that the members of this subfamily form one contiguous subfamily receptive range, suggesting that odorant receptor subfamilies do constitute functional units.
authors.affiliation: Department of Molecular and Cellular Pharmacology, Miller School of Medicine, University of Miami, Miami, Florida 33101, USA.
authors.forename: Tatjana
authors.initials: T
authors.lastname: Abaffy
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Matsunami
authors.forename: Charles W
authors.initials: CW
authors.lastname: Luetje
mesh_terms: D000818:Animals; D001681:Biological Assay / Q000379:methods; D002462:Cell Membrane / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D019005:Cystic Fibrosis Transmembrane Conductance Regulator / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D003998:Dicarboxylic Acids / Q000737:chemistry / Q000494:pharmacology; D005260:Female; D015870:Gene Expression / Q000502:physiology*; D008322:Mammals / Q000235:genetics / Q000378:metabolism*; D008564:Membrane Potentials / Q000187:drug effects / Q000235:genetics; D051379:Mice; D015394:Molecular Structure; D008970:Molecular Weight; D005810:Multigene Family; D009865:Oocytes; D018408:Patch-Clamp Techniques; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology; D043562:Receptors, G-Protein-Coupled / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D018035:Receptors, Odorant / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D012903:Smell / Q000187:drug effects / Q000235:genetics*; D014162:Transfection / Q000379:methods; D014982:Xenopus laevis
chemical_list: D003998:Dicarboxylic Acids; D012333:RNA, Messenger; D043562:Receptors, G-Protein-Coupled; D018035:Receptors, Odorant; D019005:Cystic Fibrosis Transmembrane Conductance Regulator