Genomic analysis and functional expression of canine dopamine D2 receptor.
Dopamine D2 receptor (DRD2) is one of the five dopamine receptors with seven transmembrane domains that are coupled to the G protein. We have cloned and characterized the genomic and cDNA sequences of the canine DRD2 gene, which are 12.7 and 2.7 kb in size, respectively. The genomic DNA is composed of seven exons and six introns, encoding a 443 amino acid protein with 95% amino acid identity to other mammalian D2 receptors. A length polymorphism was detected in intron 3 of the receptor gene. We also characterized alternatively spliced forms of DRD2 cDNAs, DRD2L and DRD2S. They showed a higher level of expression in midbrain and thalamus. The ratio between the long and short form is similar in RT-PCR reaction. In human and rodent, the same two spliced forms are known to be coupled to G(i)-type heterotrimeric GTP binding protein, thereby opening an inwardly rectifying potassium channel, GIRK1. When the canine DRD2L and DRD2S were heterologously expressed in Xenopus oocytes, both forms activated GIRK1 potassium channels through coupling with G(i) protein. This activation was dose-dependent, demonstrating its ligand specificity.
Myeong
H
H
National Creative Research Initiative Center for Behavioral Genetics, Department of Biological Sciences, Korea Advanced Institute of Science and Technology, 305-701, Taejon, South Korea.
Jeoung
D
D
Kim
H
H
Ha
J H
JH
Lee
Y
Y
Kim
K H
KH
Park
C
C
Kaang
B K
BK
D000595:Amino Acid Sequence; D000818:Animals; D015152:Blotting, Northern; D003001:Cloning, Molecular; D004247:DNA / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification; D018076:DNA, Complementary / Q000737:chemistry / Q000235:genetics; D004285:Dogs; D004298:Dopamine / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D005260:Female; D015870:Gene Expression; D005796:Genes / Q000235:genetics*; D005838:Genotype; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects; D008969:Molecular Sequence Data; D009865:Oocytes; D010375:Pedigree; D010802:Phylogeny; D011110:Polymorphism, Genetic; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D017448:Receptors, Dopamine D2 / Q000235:genetics* / Q000502:physiology; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D014018:Tissue Distribution; D014981:Xenopus
D018076:DNA, Complementary; D012333:RNA, Messenger; D017448:Receptors, Dopamine D2; D004247:DNA; D004298:Dopamine