Soehnge H, Huang X, Becker M, Whitley P, Conover D, Stern M
Department of Biochemistry and Cell Biology, Rice University, Houston, TX 77251, USA.
Proc Natl Acad Sci U S A. 1996 Nov 12;93(23):13262-7. doi: 10.1073/pnas.93.23.13262.
Behavioral and electrophysiological studies on mutants defective in the Drosophila inebriated (ine) gene demonstrated increased excitability of the motor neuron. In this paper, we describe the cloning and sequence analysis of ine. Mutations in ine were localized on cloned DNA by restriction mapping and restriction fragment length polymorphism (RFLP) mapping of ine mutants. DNA from the ine region was then used to isolate an ine cDNA. In situ hybridization of ine transcripts to developing embryos revealed expression of this gene in several cell types, including the posterior hindgut, Malpighian tubules, anal plate, garland cells, and a subset of cells in the central nervous system. The ine cDNA contains an open reading frame of 658 amino acids with a high degree of sequence similarity to members of the Na+/Cl(-)-dependent neurotransmitter transporter family. Members of this family catalyze the rapid reuptake of neurotransmitters released into the synapse and thereby play key roles in controlling neuronal function. We conclude that ine mutations cause increased excitability of the Drosophila motor neuron by causing the defective reuptake of the substrate neurotransmitter of the ine transporter and thus overstimulation of the motor neuron by this neurotransmitter. From this observation comes a unique opportunity to perform a genetic dissection of the regulation of excitability of the Drosophila motor neuron.
对果蝇“沉醉”（ine）基因缺陷型突变体的行为和电生理研究表明，运动神经元的兴奋性增加。在本文中，我们描述了ine基因的克隆和序列分析。通过对ine突变体进行限制性图谱分析和限制性片段长度多态性（RFLP）图谱分析，将ine基因的突变定位在克隆的DNA上。然后用来自ine区域的DNA分离出一个ine cDNA。将ine转录本与发育中的胚胎进行原位杂交，结果显示该基因在几种细胞类型中表达，包括后肠、马氏管、肛板、花环细胞以及中枢神经系统中的一部分细胞。ine cDNA包含一个658个氨基酸的开放阅读框，与Na⁺/Cl⁻依赖性神经递质转运体家族成员具有高度的序列相似性。该家族成员催化释放到突触中的神经递质的快速重摄取，从而在控制神经元功能中发挥关键作用。我们得出结论，ine突变导致果蝇运动神经元的兴奋性增加，原因是ine转运体的底物神经递质的重摄取存在缺陷，从而使该神经递质对运动神经元产生过度刺激。基于这一观察结果，我们有了一个独特的机会来对果蝇运动神经元兴奋性的调节进行遗传学剖析。
