Identification and functional characterization of the novel isoforms of bovine norepinephrine transporter produced by alternative splicing.
Analyzing variation of bovine norepinephrine transporter (NET) at the 3'-region by RT-PCR in the adrenal glands and the brain revealed four isoforms of NET produced by alternative splicing of four cassettes (C0, C1, C2 and C3) encoded by exons 12-15, designated bNET1a (C0-C1-C2, formerly designated bNET1), bNET1b (C0-C2), bNET2a (C0-C1-C3) and bNET2b (C0-C3, formerly designated bNET2), respectively. Expression of these isoforms in COS-7 cells revealed that the isoforms that contain the C1 cassette encoded by exon 13 (bNET1a and bNET2a) showed a significant increase in [(3)H]norepinephrine uptake and [(3)H]nisoxetine binding, whereas the isoforms which lack the C1 cassette (bNET1b and bNET2b) failed to display those activities despite the selection of either exon 14 or exon 15. These results suggest that the region encoded by exon 13 is indispensable for NET functional expression.
Kitayama
Shigeo
S
Department of Pharmacology, Hiroshima University Faculty of Dentistry, Kasumi 1-2-3, Minami-ku, Hiroshima 734-8553, Japan. shigeok@hiroshima-u.ac.jp
Kumagai
Kei
K
Morita
Katsuya
K
Dohi
Toshihiro
T
D017398:Alternative Splicing / Q000235:genetics*; D000818:Animals; D019556:COS Cells; D002417:Cattle; D002462:Cell Membrane / Q000378:metabolism*; D002490:Central Nervous System / Q000378:metabolism*; D018076:DNA, Complementary / Q000235:genetics / Q000302:isolation & purification; D005091:Exons / Q000235:genetics; D005473:Fluoxetine / Q000031:analogs & derivatives* / Q000494:pharmacology; D009638:Norepinephrine / Q000378:metabolism* / Q000494:pharmacology; D050484:Norepinephrine Plasma Membrane Transport Proteins; D017729:Presynaptic Terminals / Q000378:metabolism*; D011485:Protein Binding / Q000235:genetics; D020033:Protein Isoforms / Q000235:genetics / Q000302:isolation & purification; D017434:Protein Structure, Tertiary / Q000235:genetics; D027981:Symporters / Q000235:genetics / Q000302:isolation & purification*; D009435:Synaptic Transmission / Q000502:physiology*
D018076:DNA, Complementary; D050484:Norepinephrine Plasma Membrane Transport Proteins; D020033:Protein Isoforms; D027981:Symporters; D005473:Fluoxetine; C011386:nisoxetine; D009638:Norepinephrine