title: Cloning and functional characterization of a novel dopamine receptor from Drosophila melanogaster.
abstract: A cDNA clone is described that encodes a novel G-protein-coupled dopamine receptor (DopR99B) expressed in Drosophila heads. The DopR99B receptor maps to 99B3-5, close to the position of the octopamine/tyramine receptor gene at 99A10-B1, suggesting that the two may be related through a gene duplication. Agonist stimulation of DopR99B receptors expressed in Xenopus oocytes increased intracellular Ca2+ levels monitored as changes in an endogenous inward Ca2+-dependent chloride current. In addition to initiating this intracellular Ca2+ signal, stimulation of DopR99B increased cAMP levels. The rank order of potency of agonists in stimulating the chloride current is: dopamine > norepinephrine > epinephrine > tyramine. Octopamine and 5-hydroxytryptamine are not active (< 100 microM). This pharmacological profile plus the second-messenger coupling pattern suggest that the DopR99B receptor is a D1-like dopamine receptor. However, the hydrophobic core region of the DopR99B receptor shows almost equal amino acid sequence identity (40-48%) with vertebrate serotonergic, alpha 1- and beta-adrenergic, and D1-like and D2-like dopaminergic receptors. Thus, this Drosophila receptor defines a novel structural class of dopamine receptors. Because DopR99B is the second dopamine receptor cloned from Drosophila, this work establishes dopamine receptor diversity in a system amenable to genetic dissection.
authors.affiliation: Department of Biochemical Pharmacology, State University of New York at Buffalo 14260-1200, USA.
authors.forename: G
authors.initials: G
authors.lastname: Feng
authors.forename: F
authors.initials: F
authors.lastname: Hannan
authors.forename: V
authors.initials: V
authors.lastname: Reale
authors.forename: Y Y
authors.initials: YY
authors.lastname: Hon
authors.forename: C T
authors.initials: CT
authors.lastname: Kousky
authors.forename: P D
authors.initials: PD
authors.lastname: Evans
authors.forename: L M
authors.initials: LM
authors.lastname: Hall
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D002118:Calcium / Q000378:metabolism; D002874:Chromosome Mapping; D002875:Chromosomes / Q000235:genetics; D003001:Cloning, Molecular; D000242:Cyclic AMP / Q000378:metabolism; D018076:DNA, Complementary / Q000235:genetics; D029721:Drosophila Proteins / Q000235:genetics*; D004331:Drosophila melanogaster / Q000235:genetics*; D005260:Female; D019204:GTP-Binding Proteins / Q000235:genetics; D017403:In Situ Hybridization; D008969:Molecular Sequence Data; D009424:Nervous System Physiological Phenomena; D009865:Oocytes / Q000502:physiology; D012333:RNA, Messenger / Q000032:analysis; D011954:Receptors, Dopamine / Q000235:genetics*; D017447:Receptors, Dopamine D1 / Q000235:genetics*; D015290:Second Messenger Systems / Q000235:genetics; D017422:Sequence Analysis, DNA; D014981:Xenopus
chemical_list: D018076:DNA, Complementary; C000622444:Dop1R2 protein, Drosophila; D029721:Drosophila Proteins; D012333:RNA, Messenger; D011954:Receptors, Dopamine; D017447:Receptors, Dopamine D1; D000242:Cyclic AMP; D019204:GTP-Binding Proteins; D002118:Calcium