Baldwin T J, Tsaur M L, Lopez G A, Jan Y N, Jan L Y
Howard Hughes Medical Institute, University of California, San Francisco 94143-0724.
Neuron. 1991 Sep;7(3):471-83. doi: 10.1016/0896-6273(91)90299-f.
A cDNA clone encoding a K+ channel polypeptide with 72% amino acid sequence identity to Drosophila Shal was isolated from rat hippocampus. Functional expression of the cDNA in Xenopus oocytes generated 4-amino-pyridine-sensitive K+ channels displaying rapid inactivation kinetics. The fastest component of inactivation was slowed by the deletion of 3 basic residues in the amino-terminal region. Northern blots revealed that the mRNA encoding this K+ channel polypeptide was expressed at a similar level in the brain and in the heart. In situ hybridization revealed that the mRNA encoding this K+ channel appeared concentrated in the hippocampus, dentate gyrus, and habenular nucleus in the brain. Thus, this K+ channel polypeptide is likely to form some of the A-type K+ channels expressed in the mammalian nervous system and heart.
从大鼠海马体中分离出一个编码钾离子通道多肽的cDNA克隆，该多肽与果蝇Shal的氨基酸序列一致性为72%。该cDNA在非洲爪蟾卵母细胞中的功能性表达产生了对4-氨基吡啶敏感的钾离子通道，其显示出快速失活动力学。氨基末端区域3个碱性残基的缺失减缓了失活的最快组分。Northern印迹显示，编码该钾离子通道多肽的mRNA在脑和心脏中的表达水平相似。原位杂交显示，编码该钾离子通道的mRNA在脑中集中出现在海马体、齿状回和缰核中。因此，这种钾离子通道多肽可能构成哺乳动物神经系统和心脏中表达的一些A型钾离子通道。
