Molecular analysis and sensitivity to arachidonic acid of voltage-dependent KィイD1+ィエD1 channel, Kv4.3

原位杂交和RT-PCR分析显示，在具有不同c端胞质结构域的3个Kv4.3剪接变体（a、b和c）中，Kv4.3a的mRNA在大脑皮层、小脑、嗅球和延髓中富集，而Kv4.3c的mRNA主要集中在海马中。利用RT-PCR技术从大鼠脑中分离到Kv4.3的3个不同的剪接变异体（Kv4.3 3d、e和f），它们分别由601、635和628个氨基酸组成，具有不同的c端胞质结构域。kv43 b、d、e、f在脑组织中的表达水平较低。在HEK293细胞的异源表达中，通过诱变去除Kv4.3a c端结构域的149个氨基酸，显著降低了Kv4.3a的失活恢复速度。然而，令人惊讶的是，无论是失活率还是激活和失活的电压依赖性都没有改变。

In situ hybridization and RT-PCR analyses has 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 of 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 divergent C-terminal cytoplasmic domains, were isolated from rat brain by RT-PCR. Kv4.3b, d, e and f are 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.