Cloning and expression of a 5-hydroxytryptamine7 receptor positively coupled to adenylyl cyclase.
A cDNA clone (designated as GP2-7) encoding a novel 5-hydroxytryptamine (5-HT) receptor was isolated from a guinea pig hippocampal library. The receptor shares amino acid homology within the hydrophobic domains with other cloned 5-HT receptor subtypes (34-48%). The sequence of GP2-7 is homologous to that described for a novel receptor previously cloned from a rat brain cDNA library and provisionally designated as 5-HT7. mRNA for GP2-7 was detected in cortical and limbic brain regions. Transiently expressed GP2-7 showed high-affinity binding to [3H]5-HT (pKi = 9.0) with the following rank order of affinities: 5-carboxyamidotryptamine (5-CT) > 5-HT = 5-methoxytryptamine (5-MeOT) > methiothepin > 8-hydroxy-2-(dipropylamino)tetralin (8-OH-DPAT) > spiperone >> sumatriptan. Adenylyl cyclase activity in CHO-K1 cells transiently transfected with GP2-7 was stimulated by several analogues of 5-HT with the following order of potency: 5-CT > 5-HT = 5-MeOT > dipropyl-5-CT > 8-OH-DPAT. Methiothepin and spiperone were potent antagonists. Preliminary analysis suggests that GP2-7 closely resembles a receptor in the guinea pig hippocampus that exhibits a high affinity toward 5-CT.
Tsou
A P
AP
Institute of Bio-Organic Chemistry, Syntex Discovery Research, Palo Alto, California 94304.
Kosaka
A
A
Bach
C
C
Zuppan
P
P
Yee
C
C
Tom
L
L
Alvarez
R
R
Ramsey
S
S
Bonhaus
D W
DW
Stefanich
E
E
D000262:Adenylyl Cyclases / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D001667:Binding, Competitive; D015152:Blotting, Northern; D001921:Brain / Q000378:metabolism*; D016466:CHO Cells; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D003001:Cloning, Molecular / Q000379:methods; D006224:Cricetinae; D015870:Gene Expression; D015723:Gene Library; D006168:Guinea Pigs; D006624:Hippocampus / Q000378:metabolism*; D017403:In Situ Hybridization; D007700:Kinetics; D051379:Mice; D008969:Molecular Sequence Data; D010802:Phylogeny; D011061:Poly A / Q000302:isolation & purification / Q000378:metabolism; D012313:RNA / Q000302:isolation & purification / Q000378:metabolism; D012333:RNA, Messenger / Q000032:analysis / Q000378:metabolism; D011869:Radioligand Assay; D051381:Rats; D011985:Receptors, Serotonin / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D012701:Serotonin / Q000378:metabolism; D014162:Transfection
D012333:RNA, Messenger; D011985:Receptors, Serotonin; D011061:Poly A; D012701:Serotonin; D012313:RNA; D000262:Adenylyl Cyclases