RUI: PTL-1, A Tau-Like Microtubule Binding Protein in C. elegans

RUI：PTL-1，秀丽隐杆线虫中的 Tau 样微管结合蛋白

• 批准号: 9604180
• 负责人: Stephanie Aamodt
• 金额: $ 10.54万
• 依托单位: Louisiana State University Shreveport
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-07-01 至 2002-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9604180&HistoricalAwards=false
• 关键词: RUI; PTL; Tau; Like; Microtubule

9604180 Aamodt Technical Abstract: The mammalian tau microtubule-associated proteins have been implicated in axonal outgrowth, microtubule spacing and microtubule bundling. A caenorhabditis elegans gene with homology to the repeat region of tau was identified and characterized. This gene was named ptl-1 for Protein with Tau-Like repeats. The ptl-1 transcript, like mammalian tau transcripts, is alternatively spliced to produce messages that encode proteins with variable numbers of repeats. The predicted ptl-1 products have strong sequence homology to tau over the repeat region and are similar to tau in size, amino acid content, charge distribution, predicted secondary structure, hydrophobicity , and flexibility Bacterially expression PTL-1 bound to microtubules in vitro. These results show that tau-like proteins evolved early and suggests that they may be present in many different phyla. C. elegans is a powerful system amenable to genetic, molecular and cellular analysis in which to study the functions of the tau class of proteins. Three major questions will be addressed: Does PTL-1 promote tubulin polymerization in a manner similar to that of mammalian tau? Where is the gene expressed? And what is the function of the gene product? Recombinant PTL-1 will be tested to determine whether it increases microtubule nucleation and assembly in vitro as tau does. Antibodies will be produced against PTL-1 and ptl-1::lacZ fusion genes will be made to determine when and where ptl-1 is expressed. Finally, a strain of C. elegans that does not express ptl-1 will be made. If absence of ptl-1 induces a phenotype, the mammalian tau gene will be expressed to determine whether it can rescue. These studies will provide information about the role of ptl-1 in C. elegans and the relationship between PTL-1 and tau. The relevant of this project derives from its contribution to our understanding of basic cellular and developmental mechanisms. Lay Abstract: Microtubules are fundamentally important structures in eukaryotic cells. They function in cellular and intracellular motility, serving as the means whereby cilia and flagella beat, chromosomes are distributed to daughter cells during cell division, cellular extensions are properly shaped and oriented, and intracellular components are moved from one part of the cell to another. These last two functions are notably critical in neuronal cells that bear extremely long axons (some axons in higher animals may be several feet in length!). The axons need to connect the cell bodies to the right terminal point elsewhere in the body, and neuroexcitatory and other materials need to be transported from their site of synthesis in the cell body to the terminal end of the axon in order for the neuron to function properly. Many accessory proteins are known that bind to microtubules and are somehow involved in their proper formation and/or function; these are known collectively as Microtubule-Associated Proteins, or MAPs. One of the predominant MAPs in neuronal cells is called tau, and although it has been studied extensively in mammalian systems, there are still many fundamental questions about tau's function in the cell that remain unanswered. In this project, the recent discovery of a tau-like protein in the simple model organism, C. elegans (a nematode worm), will be exploited. The simplicity and well-established background information about the worm, together with the power of genetics, will allow new discoveries about the function of this tau-like protein in both the worm and other animals. ***

摘要：哺乳动物tau微管相关蛋白与轴突生长、微管间距和微管捆绑有关。鉴定了一个与tau重复区同源的秀丽隐杆线虫基因。该基因被命名为ptl-1，代表tau样重复序列的蛋白。ptl-1转录物，像哺乳动物的tau转录物一样，被选择性地剪接以产生具有可变重复次数的编码蛋白质的信息。预测的ptl-1产物在重复区域上与tau具有很强的序列同源性，并且在大小、氨基酸含量、电荷分布、预测的二级结构、疏水性和柔韧性方面与tau相似。这些结果表明，tau样蛋白进化得较早，并表明它们可能存在于许多不同的门中。秀丽隐杆线虫是一个强大的系统，适合遗传，分子和细胞分析，其中研究tau类蛋白质的功能。将解决三个主要问题：PTL-1是否以类似于哺乳动物tau蛋白的方式促进微管蛋白聚合？基因在哪里表达？基因产物的功能是什么？将对重组PTL-1进行测试，以确定它是否像tau一样在体外增加微管成核和组装。将产生针对PTL-1和PTL-1::lacZ融合基因的抗体，以确定PTL-1在何时何地表达。最后，一株不表达ptl-1的秀丽隐杆线虫将被制造出来。如果缺乏ptl-1诱导表型，哺乳动物tau基因将表达，以确定其是否可以拯救。这些研究将提供ptl-1在秀丽隐杆线虫中的作用以及ptl-1与tau之间的关系的信息。这个项目的相关性源于它对我们理解基本细胞和发育机制的贡献。摘要：微管是真核细胞的重要结构。它们在细胞和细胞内运动中起作用，作为纤毛和鞭毛跳动的手段，在细胞分裂期间染色体分布到子细胞，细胞延伸的形状和方向正确，细胞内成分从细胞的一部分移动到另一部分。后两种功能在具有极长轴突的神经元细胞中尤为重要（一些高等动物的轴突可能有几英尺长！）轴突需要将细胞体与身体其他部位的正确终点连接起来，神经兴奋性物质和其他物质需要从它们在细胞体内的合成点运输到轴突的末端，以使神经元正常工作。已知许多辅助蛋白与微管结合，并以某种方式参与其正常形成和/或功能；这些蛋白统称为微管相关蛋白（MAPs）。神经细胞中主要的map之一被称为tau，尽管它已经在哺乳动物系统中得到了广泛的研究，但关于tau在细胞中的功能仍有许多基本问题尚未得到解答。在这个项目中，将利用最近在简单模式生物秀丽隐杆线虫（一种线虫）中发现的一种tau样蛋白。关于这种蠕虫的简单和完善的背景信息，再加上遗传学的力量，将使人们能够在这种蠕虫和其他动物身上发现这种类似tau蛋白的功能。＊＊＊