Dominant negative isoform of rat norepinephrine transporter produced by alternative RNA splicing.
We have cloned from rat brain a family of alternatively spliced cDNAs from a single gene, which encodes a norepinephrine transporter (NET) having variations at the 3'-region including both coding and noncoding regions. This produces two transporter isoforms, rNETa and rNETb, which differ at their COOH termini. The rNETa isoform reveals a COOH terminus homologous to human NET and transports norepinephrine. In contrast, rNETb revealed no detectable transport function but reduced functional expression of rNETa when both isoforms were expressed in the same cell. Thus, rNETb potentially functions as a dominant negative inhibitor of rNETa activity. Co-expression of rNETb with a gamma-aminobutyric acid transporter (rGAT1), a serotonin transporter (rSERT), and a dopamine transporter (rDAT) reduced their transport activity. No reduction was found with the glutamate/aspartate transporter (rGLAST). Alternative RNA splicing of NET suggests a novel mechanism for the regulation of synaptic transmission.
Kitayama
S
S
Department of Pharmacology, Hiroshima University School of Dentistry, Kasumi 1-2-3, Minami-ku, Hiroshima 734, Japan. shigeok@ipc.hiroshima-u.ac.jp
Ikeda
T
T
Mitsuhata
C
C
Sato
T
T
Morita
K
K
Dohi
T
T
D017398:Alternative Splicing; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002352:Carrier Proteins / Q000235:genetics*; D003001:Cloning, Molecular; D017931:DNA Primers; D018076:DNA, Complementary; D006801:Humans; D008297:Male; D008969:Molecular Sequence Data; D009638:Norepinephrine / Q000378:metabolism*; D050484:Norepinephrine Plasma Membrane Transport Proteins; D020033:Protein Isoforms / Q000235:genetics*; D051381:Rats; D017207:Rats, Sprague-Dawley; D027981:Symporters
D002352:Carrier Proteins; D017931:DNA Primers; D018076:DNA, Complementary; D050484:Norepinephrine Plasma Membrane Transport Proteins; D020033:Protein Isoforms; C493227:SLC6A2 protein, human; C493226:Slc6a2 protein, rat; D027981:Symporters; D009638:Norepinephrine