Identification and characterization of a truncated variant of the 5-hydroxytryptamine(2A) receptor produced by alternative splicing.
We have identified an alternatively spliced 5-hydroxytryptamine 2A receptor (5-HT(2A)-R) transcript by PCR of human brain cDNA using degenerate oligonucleotide primers to transmembrane (TM) domains 3 and 7 of the 5-HT(2)-R subfamily. The variant contains a 118-bp insertion at the exon II/III boundary of the 5-HT(2A)-R, which produces a frame shift in the coding sequence and a premature stop codon. PCR analysis showed that the truncated receptor (5-HT(2A-tr)) and native 5-HT(2A)-R were co-expressed in most brain tissues, with the highest levels being found in hippocampus, corpus collosum, amygdala and caudate nucleus. Western blot analysis of HEK-293 cells transfected transiently with a 5-HT(2A-tr) construct showed that a 30-kDa protein was expressed on cell membranes. Co-transfection studies showed no effect of the 5-HT(2A-tr) variant on 3H-ketanserin binding to the native 5-HT(2A)-R or on functional coupling of the 5-HT(2A)-R to 5-HT-stimulated Ca(2+) mobilization. The functional significance of the 5-HT(2A-tr) variant and other truncated receptors remains to be established.
Guest
P C
PC
Neuroscience Research Centre, Merck, Sharp & Dohme Research Laboratories, Essex, Harlow, UK. paul_guest@merck.com
Salim
K
K
Skynner
H A
HA
George
S E
SE
Bresnick
J N
JN
McAllister
G
G
D000595:Amino Acid Sequence / Q000235:genetics; D001483:Base Sequence / Q000235:genetics; D001921:Brain / Q000378:metabolism; D002460:Cell Line; D003001:Cloning, Molecular; D014644:Genetic Variation / Q000235:genetics*; D006801:Humans; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000235:genetics / Q000378:metabolism; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000378:metabolism; D044402:Receptor, Serotonin, 5-HT2A; D011985:Receptors, Serotonin / Q000235:genetics* / Q000378:metabolism; D014018:Tissue Distribution; D014162:Transfection
D010446:Peptide Fragments; D012333:RNA, Messenger; D044402:Receptor, Serotonin, 5-HT2A; D011985:Receptors, Serotonin