Drewe J A, Verma S, Frech G, Joho R H
Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, Texas 77030.
J Neurosci. 1992 Feb;12(2):538-48. doi: 10.1523/JNEUROSCI.12-02-00538.1992.
Different types of K+ channels play important roles in many aspects of excitability. The isolation of cDNA clones from Drosophila, Aplysia, Xenopus, and mammals points to a large multigene family with several distinct members encoding K+ channels with unique electrophysiological and pharmacological properties. Given the pivotal role K+ channels play in the fine tuning of electrical properties of excitable tissues, we studied the spatial and temporal basis of K+ channel diversity. We report the isolation of two putative K+ channels that define two new subfamilies based upon amino acid sequence similarities with other known K+ channels. Northern blot and in situ hybridization studies revealed differences in the spatial and temporal expression patterns for these two new clones along with mRNAs from other K+ channel subfamilies. Two of the K+ channels studied are predominantly expressed in the brain. One of the "brain-specific" K+ channels is first expressed after about 2 weeks of postnatal cerebellar development and remains at levels about 10-fold higher in the cerebellum than in the rest of the brain.
不同类型的钾离子通道在兴奋性的诸多方面发挥着重要作用。从果蝇、海兔、非洲爪蟾和哺乳动物中分离出的cDNA克隆表明，存在一个庞大的多基因家族，其中有几个不同的成员编码具有独特电生理和药理特性的钾离子通道。鉴于钾离子通道在可兴奋组织电特性的精细调节中所起的关键作用，我们研究了钾离子通道多样性的空间和时间基础。我们报告了两个推定的钾离子通道的分离情况，这两个通道基于与其他已知钾离子通道的氨基酸序列相似性，定义了两个新的亚家族。Northern印迹和原位杂交研究揭示了这两个新克隆以及来自其他钾离子通道亚家族的mRNA在空间和时间表达模式上的差异。所研究的两个钾离子通道主要在大脑中表达。其中一个“大脑特异性”钾离子通道在出生后小脑发育约2周后首次表达，并且在小脑中的水平比大脑其他部位高约10倍。
