Biochemical and Functional Characterizations of Dyskerin Complexes

在过去的十年中，含RNA的酶复合物的研究获得了很大的动力。尽管有这种上升，关于许多含RNA酶的组装和精确的细胞功能的细节仍然很不清楚。了解这些细胞过程无疑将揭示对人类健康至关重要的生物学途径。Dyskerin是一种管家酶，参与两个重要的涉及酶RNA的细胞过程：染色体末端的修复和蛋白质合成的调节。dyskerin基因座中的遗传突变导致具有重叠表型的多种人类疾病。目前，这些遗传变化影响dyskerin在含RNA的酶复合物中的多种功能的具体机制，以及在多大程度上，尚不清楚。 我目前和拟议中的项目包括dyskerin功能的生物化学和细胞生物学研究，以及它的活性如何影响其他核糖核蛋白。我们的第一个项目将集中在dyskerin的调节作用，在染色体末端的维护RNA酶端粒酶。我们将通过测量酶复合物形成的速率来确定dyskerin序列变化导致端粒酶-RNA稳定性丧失的机制。我们的第二个项目将探讨dyskerin的RNA修饰功能的结构-功能关系，涉及细胞蛋白质合成能力的调节。我们将研究单个位点特异性假尿苷残基的丢失如何影响由核糖体（蛋白质合成机器）介导的正常和应激诱导的蛋白质合成途径。我们还将测量次优核糖体RNA修饰的生理后果（细胞活力）。我们的数据将确定含有dyskerin的复合物负责其多种细胞活动的精确分子特征，并绘制变化可能影响这些细胞作用的机制。 对含有RNA的酶复合物及其功能的研究揭示了DNA-蛋白质关系的中心法则的许多例外。我们的研究将通过推断dyskerin-RNA复合物如何调节生物途径的功能并影响正常生理学来对此做出贡献。此外，这项研究将提供信息来预测遗传变异dyskerin亚型的基因型-表型关系，并将有助于核糖体功能调控的建模。

Research of RNA-containing enzyme complexes has gained much momentum in the past decade. Despite this upswing, details about the assembly, and the precise cellular functions, of many RNA-containing enzymes have remained poorly defined. Understanding these cellular processes will undoubtedly reveal biological pathways essential to human health. Dyskerin is a housekeeping enzyme that participates in two important cellular processes involving enzymatic RNAs: the repair of chromosome ends, and the regulation of protein synthesis. Heritable mutations in the dyskerin locus lead to multiple human diseases with overlapping phenotypes. At present, the specific mechanisms by which these genetic changes impact dyskerin’s multiple functions in RNA-containing enzyme complexes, and to what extent, are not known. My current and proposed projects include biochemical and cell-biology studies of dyskerin functions, and how its activity impacts other ribonucleoproteins. Our first project will focus on dyskerin’s regulatory roles in chromosome-end maintenance by the RNA-enzyme telomerase. We will determine the mechanism by which changes in dyskerin sequence leads to a loss in telomerase-RNA stability, by measuring the rate of enzymatic complex formation. Our second project will probe the structure-function relationship of dyskerin’s RNA modification functions, implicated in the regulation of cellular protein synthesis capacity. We will study how the loss of individual site-specific pseudouridine residues impacts both normal, and stress-induced, protein synthesis pathways mediated by ribosomes, the protein-synthesis machinery. We will also measure the physiological consequences (cell viability) of sub-optimal ribosomal RNA modification. Our data will identify the precise molecular characteristics of dyskerin-containing complexes responsible for its multiple cellular activities, and map the mechanisms by which changes can affect these cellular roles. Studies of RNA-containing enzyme complexes and their functions have revealed many exceptions to the central dogma of the DNA-protein relationship. Our study will contribute to this by deducing how dyskerin-RNA complexes modulate the functions of biological pathways and impact normal physiology. In addition, this study will provide information to predict genotype-phenotype relationships for inheritance of variant dyskerin isoforms, and will contribute to the modeling of ribosomal function regulation.