PHYSIOLOGY OF EXCITABLE MEMBRANE AND SYNAPSE

单基因突变可用于改变任何给定的大分子或 兴奋细胞中的细胞过程。 一群变种人 应该能让我们解剖出 兴趣 这项拟议中的研究涉及果蝇突变体， 神经和肌肉中膜电流的特定缺陷。 在果蝇中发现了三种不同的外向钾电流 肌肉. 短暂性IA、延迟整流IK和Ca++依赖性 IC. 这些K+电流分别被Sh、eag、Hk和Eag改变 突变。 我们将对这些电流进行电压钳分析， 幼虫肌肉表征激活和失活特性， 这些离子通道的离子选择性和药理学敏感性 以及突变改变的机制。 使用膜片钳， 全细胞钳技术，我们将扩大这一分析，以检查 突变对培养的果蝇神经元中K+通道的影响。 在 此外，存在于神经中的Na电流的特定改变， 而不是肌肉，由nap ts和帕拉ts突变引起。 单通道和全细胞电流实验可以提供一个精辟的 分析这些突变改变的分子机制。 先前对果蝇的研究表明，某些类型的通道可能 由子单元组成，并且可以与其他通道共享某些子单元 类型 将通过研究 单基因突变对不同通道的影响以及 一种由不同基因突变引起的通道类型。 功能 基因产物之间的关系可以通过分析 相同基因的不同突变（等位基因）之间的相互作用，或 杂合子或双突变个体中不同基因的突变。 我们将尝试将这些功能分析与重组 通过对EAG、帕拉ts和nap ts等位基因的DNA研究， 通道和相关蛋白质的功能。

Single-gene mutations can be used to alter any given macromolecule or cellular process in the excitable cells. A proper collection of mutants should enable us to dissect the cellular structures or mechanisms of interest. The proposed research involves Drosophila mutants that have specific defects in membrane currents in nerve and muscle. Three different outward K+ currents have been identified in Drosophila muscles. The transient IA, delayed rectification IK, and Ca++ -dependent IC. These K+ currents are separately altered by Sh, eag, Hk and slo mutations. We will conduct voltage-clamp analysis of these currents in larval muscles to characterize the activation and inactivation properties, ionic selectivity and pharmacological sensitivity of these ionic channels and the mechanisms altered by the mutations. Using the patch-clamp and whole-cell clamp techniques we will extend this analysis to examine the mutational effects on the K+ channels in cultured Drosophila neurons. In addition, the specific alterations in Na current, which is present in nerve but not muscle, caused by nap ts and para ts mutations will be studied. Single-channel and whole-cell current experiments can provide an incisive analysis of the molecular mechanisms altered by these mutations. Previous studies in Drosophila suggest that certain types of channels may be composed of subunits and may share some subunits with other channel types. This possibility will be further investigated by studying the effects of a single-gene mutation on different channels and alterations in a channel type caused by mutations of different genes. The functional relationship among the gene products can be revealed by analysis of inter-actions between different mutations (alleles) of the same gene or mutations of different genes in heterozygous or double-mutant individuals. We will attempt to integrate these functional analysis with the recombinant DNA studies of the alleles of eag, para ts and nap ts in order to relate structure to function for channels and related proteins.