Regulation of the Neuronal Promoter of Calcium-Activated Potassium Channel Gene

摘要 小行星9724088 不同类型的神经元必须有不同的电活动模式，神经系统才能正常工作。 例如，启动运动的神经元通常会以高频率的动作电位爆发来“激发”，而控制缓慢、节律性行为的神经元可能只会缓慢地激发，但时间非常精确。 神经元产生特定活动模式的能力由其表达的离子通道的类型和数量决定。 阿特金森博士和他的学生将研究果蝇中离子通道基因的转录调控。 这种基因被称为“慢波”，它产生一种钙激活的钾通道，这种通道在设定各种神经元类型的活动模式中起着至关重要的作用。 任何基因的表达都是由基因的特定区域控制的，称为转录控制区。 在慢波的情况下，在转录控制区内有四种不同的启动子序列，它们负责不同组织中的差异表达。 一些启动子改变基因产物的量，而另一些则改变编码通道的氨基酸序列，从而改变其结构。 这种变化可以极大地改变神经元的放电模式范围。 阿特金森博士的实验室克隆了慢人的整个转录控制区。 他们现在计划系统地将缺失引入该区域，以精确定位负责不同神经元亚型表达的转录控制元件。 然后通过将这些控制元件作为单个寡核苷酸序列重新引入来验证它们的功能，如果元件已被正确鉴定，则该寡核苷酸序列应恢复表达模式。 在该项目的最后一部分，他们将使用几种技术来鉴定产生结合每个转录控制元件的转录因子的基因。 这项工作的结果将帮助我们了解神经元如何获得离子通道数量和类型的微妙差异，它们需要发挥不同的功能作用。

ABSTRACT 9724088 ATKINSON Different types of neurons must have different patterns of electical activity for the nervous system to function properly. For example, neurons that initiate movement often "fire" with high-frequency burst of action potentials, whereas neurons that control slow, rythmic behaviors may fire only slowly, but with very precise timing. A neuron's ability to generate specific activity patterns is determined by the types and numbers of ion channels it expresses. Dr. Atkinson and his students will investigate the transcriptional regulation of an ion channel gene in the fruitfly Drosophila melanogaster. The gene, called "slowpoke," produces a calcium-activated potassium channel, which is crucially involved in setting activity patterns in a variety of neurons types. The expression of any gene is controlled by specific areas of the gene called the transciptional control region. In the case of slowpoke, there are four different promoter sequences within the transciptional control region that are responsible for differential expression in different tissues. Some of the promoters alter the amount of the gene product, whereas others alter the amino acid sequence, and thus the structure, of the encoded channel. Such changes can dramatically alter a neuron's range of firing patterns. Dr. Atkinson's laboratory has cloned the entire transcriptional control region of slowpoke. They now plan to systematically introduce deletions into the region to precisely locate the transcriptional control elements responsible for expression in different neuronal subtypes. The function of these control elements will then be verified by re-introducing them as single oligonucleotide sequences, which should restore the expression pattern, if the elements have been properly identified. In the final part of the project, they will use several techniques to identify genes that produce the transcription factors that bind each of the transcription control element. The results of this work will help us understand how neurons acquire the sometimes subtle differences in ion channel number and type they need to play different functional roles.