Regional expression of the splice variants of Kv4.3 in rat brain and effects of C-terminus deletion on expressed K+ currents.
In situ hybridization and RT-PCR analyses have revealed that, among three Kv4.3 splice variants (a, b, and c) with distinct C-terminal cytoplasmic domains, the mRNA for Kv4.3a is abundant in cerebral cortex, cerebellum, olfactory bulb, and medulla oblongata, whereas the mRNA for Kv4.3c is localized mainly to hippocampus. Three new distinct splice variants of Kv4.3 (Kv4.3d, e and f), which consist of 601, 635, and 628 amino acids, respectively, and have distinct C-terminal cytoplasmic domains, were isolated from rat brain by RT-PCR. Kv4.3b, d, e and f were expressed at much lower levels in brain. Mutagenesis which removed 149 amino acids in C-terminal domain of Kv4.3a significantly slowed its rate of recovery from inactivation as measured in heterologous expression in HEK293 cells. Surprisingly, however, neither the rate of inactivation nor voltage dependence of the activation and inactivation were changed.
Department of Molecular and Cellular Pharmacology, Faculty of Pharmaceutical Sciences, Nagoya City University, Nagoya, Japan.
S
S
Ohya
M
M
Tanaka
T
T
Oku
T
T
Furuyama
N
N
Mori
W R
WR
Giles
M
M
Watanabe
Y
Y
Imaizumi
D000595:Amino Acid Sequence; D000818:Animals; D001923:Brain Chemistry; D017353:Gene Deletion; D017403:In Situ Hybridization; D008297:Male; D008969:Molecular Sequence Data; D015221:Potassium Channels / Q000737:chemistry / Q000235:genetics* / Q000502:physiology; D024642:Potassium Channels, Voltage-Gated; D020033:Protein Isoforms; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017208:Rats, Wistar; D020133:Reverse Transcriptase Polymerase Chain Reaction; D051672:Shal Potassium Channels
C497023:Kcnd3 protein, rat; D015221:Potassium Channels; D024642:Potassium Channels, Voltage-Gated; D020033:Protein Isoforms; D012333:RNA, Messenger; D051672:Shal Potassium Channels