Analysis of Voltage-gated Ion Channels in Antarctic Fish

该项目研究生活在南极洲的鱼类的神经和肌肉的蛋白质如何在寒冷中发挥作用，这将提供有关这些蛋白质在包括人类在内的所有动物中的功能的信息。这些蛋白质被称为离子通道，它们的打开和关闭使离子（带电荷的原子或分子）流入或流出细胞，从而引起神经和肌肉的电活动。影响这一过程的突变是许多人类疾病如癫痫、心律失常和肌肉麻痹的基础。因此，了解蛋白质的哪些部分控制这些转变是很重要的。通道开启和关闭的速度取决于温度。人体离子通道在寒冷时转变缓慢，这就是我们在寒冷中麻木的原因。然而，南极的鱼类，被称为冰鱼，在极低的温度下活动，这极大地限制了人类离子通道的活动。研究人员有证据表明，冰鱼离子通道的特定变化使它们的通道在寒冷中运作不同，他们将使用基因发现和生物物理学方法来测试这些变化如何改变冰鱼蛋白质在不同温度下的转变。该项目还将进一步实现国家科学基金会培养新一代科学家和向公众提供科学发现的目标。基因发现分析将由包括少数民族大学学生在内的本科生完成，调查人员将开发一门新课程，也将为该机构和其他地方的学生提供服务。此外，调查人员将参与与公众以及有特殊需要的团体的教育外展活动。南极鱼是南极洲最成功的脊椎动物群之一。Notothens已经适应了它们所居住的冰冷的水，这个项目将研究它们的电压门控离子通道（vgic）在寒冷中的功能。离子通道的分子运动受到寒冷的严重损害，然而，在足以使温带“冷血”动物的神经和肌肉瘫痪的温度下，没有一种离子通道能够正常工作。令人惊讶的是，目前还没有对这些vgic进行生物物理或分子研究。研究人员有初步数据表明，氨基酸取代发生在从果蝇到人类的进化保守的vgic位点上。已知其中一些位点影响通道功能，而其他位点在通道过渡中的作用尚不清楚。研究它们的结果将提供新的信息，也适用于非地球生物，甚至可能是人类，vgic，以及为vgic如何适应寒冷提供见解。该项目将使用电压钳技术对两种vgic进行生物物理表征，并将其在一定温度范围内的特性与两种温带鱼类的相同通道进行比较。独特的notothen氨基酸取代的作用将以诱变为特征。一个具体的目标将是一个项目，在这个项目中，本科生将挖掘notothen序列数据库，以确定vgic中可能促进适应寒冷的其他潜在氨基酸取代。

This project studies how the proteins of the nerves and muscles of fish that live in Antarctica function in the cold, which should provide information on the function of these same proteins in all animals, including humans. These proteins, called ion channels, open and close to allow ions (atoms or molecules with electrical charge) to flow into or out of cells which causes the electrical activity of nerves and muscles. Mutations that influence this process are the basis of numerous human disorders such as epilepsy, heart arrhythmias, and muscle paralysis. Thus, it is important to understand what parts of the proteins govern these transitions. The speed with which channels open and close depends on temperature. Human ion channels transition slowly when we are cold, which is why we become numb in the cold. Yet Antarctic fish, called icefish, are active at freezing temperatures that drastically limit the activity of human ion channels. The investigators have evidence that specific alterations in the icefishs' ion channels allow their channels to operate differently in the cold and they will use gene discovery and biophysical methods to test how these changes alter the transitions of icefish proteins at different temperatures. The project will also further the NSF goals of training new generations of scientists and of making scientific discoveries available to the general public. The gene discovery analysis will be done by undergraduate students including those from a minority-serving university and the investigators will develop a new course which will also serve students at that institution and elsewhere. In addition, the investigators will participate in educational outreach events with the general public as well as with groups with special needs.Notothenioid fishes are one of the most successful groups of vertebrates in Antarctica. Notothens have adaptations to the freezing water they inhabit and this project will study how their voltage-gated ion channels (VGICs) function in the cold. The molecular movements of ion channels are severely impaired by cold, yet notothens function at temperatures that would paralyze the nerves and muscles of "cold-blooded" temperate zone animals. Surprisingly, no biophysical or molecular investigations have been conducted on notothen VGICs. The investigators have preliminary data that amino acid substitutions occur at sites in VGICs that are evolutionarily conserved from fruit flies to humans. Some of these sites are known to impact channel function and the role of others in channel transitioning are unknown. The results from studying them will provide novel information also applicable to non-notothen, perhaps even human, VGICs as well as providing insights into how VGICs adapt to the cold. The project will biophysically characterize notothen VGICs using voltage-clamp techniques will and compare their properties over a range of temperatures to the same channel from two temperate zone fish. The role of unique notothen amino acid substitutions will be characterized by mutagenesis. One specific aim will be a project in which undergraduates mine notothen sequence databases to identify other potential amino acid substitutions in VGICs that might facilitate adaptation to the cold.