Chopra M, Gu G G, Singh S
Department of Biochemical Pharmacology, 308, Hochstetter Hall, State University of New York at Buffalo, Buffalo, NY 14260-1200, USA.
J Neurogenet. 2000 Jun;14(2):107-23. doi: 10.3109/01677060009083478.
Mutations and pharmacological agents have been used to resolve and analyze several K(+) currents in Drosophila. Mutations that affect channels carrying the voltage-activated I(A) and the Ca(2+) -activated I(CF) have helped greatly in analyzing the structure, function and regulation of these channels. We now report mutations that selectively affect the delayed rectifier current, I(K). Flies mutagenized with ethylmethanesulfonate were screened for temperature-induced paralysis. Paralytic mutants identified in the screen were examined for K(+) currents in the larval body-wall muscles. The z66 mutant larvae showed a significant reduction in I(K). The mutation did not affect other K(+) currents (I(A), I(CF), or I(CS) ) or the Ca(2+) channel current in the muscles. Another mutation, z4, which showed reduced I(K), failed to complement z66. Genetic analysis localized the gene disrupted by z66 and z4 to the left arm of chromosome 3, in the 63A1-63B6 region on polytene chromosomes. The z66 and the z4 mutations, which lie in the Shab K(+) channel gene, provide an opportunity to undertake analysis of the functioning of these channels and to study the role of these channels in membrane excitability.
突变和药物制剂已被用于解析和分析果蝇中的几种钾离子电流。影响携带电压激活型I(A)和钙激活型I(CF)通道的突变，在分析这些通道的结构、功能和调节方面有很大帮助。我们现在报告选择性影响延迟整流电流I(K)的突变。用乙基甲磺酸诱变果蝇，筛选温度诱导的麻痹。在筛选中鉴定出的麻痹突变体，检测其幼虫体壁肌肉中的钾离子电流。z66突变体幼虫的I(K)显著降低。该突变不影响肌肉中的其他钾离子电流（I(A)、I(CF)或I(CS)）或钙离子通道电流。另一个显示I(K)降低的突变体z4，不能与z66互补。遗传分析将z66和z4破坏的基因定位到3号染色体左臂，在多线染色体的63A1-63B6区域。位于Shab钾离子通道基因中的z66和z4突变，为分析这些通道的功能以及研究这些通道在膜兴奋性中的作用提供了机会。
