FUNCTION OF THE RO RIBONUCLEOPROTEINS AND THE LA PROTEIN

该项目的总体目标是确定两个 保守的细胞成分，Ro核糖核蛋白颗粒(RNPs) 和La蛋白。这两个细胞组件是经常攻击的目标 系统性红斑狼疮患者自身免疫反应的研究 和干燥综合征。此外，母体抗Ro和抗La 抗体与完全性先天性心脏传导阻滞高度相关 新生儿。Ro RNPs由一个60千道尔顿的蛋白质组成(可能 附加蛋白质)结合了几个小的RNA分子中的一个 全长约100个核苷酸。尽管这些粒子看起来 所有脊椎动物细胞的组成部分，它们的亚细胞位置是 有争议，它们的功能尚不清楚。Ro RNPs的一个子集 还与La蛋白结合，La蛋白是一种50kd的磷酸蛋白，可结合所有已知的 RNA聚合酶III在其生物发生的早期转录本。尽管 La蛋白被认为是转录所必需的 被RNA聚合酶III终止，有可能这种蛋白质 在聚合酶III RNA生物发生的某些其他方面的功能。 像Ro RNPs一样，La蛋白在各种不同的 脊椎动物细胞。此外，具有相似生化的蛋白质 与哺乳动物La蛋白一样的特征已在 线虫和酵母。 Ro RNPs和Ro RNPs的普遍分布和表观守恒 La蛋白认为它们是真核生物的重要组成部分 细胞。这项提案的第一个目标是最终确定 利用抗体和核酸对Ro RNPs进行亚细胞定位 探测器。第二个目标是识别与之相互作用的分子 补骨脂素与紫外光交联免疫共沉淀的RO RNPs 带有抗Ro抗体。第三个目标是识别Ro RNPs和 生物体中的La蛋白，这将允许遗传方法发挥作用。 Ro RNPs与La蛋白同源基因的鉴定 无论是果蝇、线虫还是酵母菌都能让我们评估 从基因上耗尽细胞和细胞中这些成分的后果 并从基因上识别与Ro RNPs相互作用的因素 和La蛋白。这些保守分子的功能的确定 细胞组件将扩展我们对基本细胞过程的知识 也可能为为什么这些粒子是频繁的目标提供线索 某些自身免疫性疾病的免疫反应。

The overall objective of the project is to determine the functions of two conserved cellular components, the Ro ribonucleoprotein particles (RNPs) and the La protein. These two cellular components are frequent targets of the autoimmune response in patients with systemic lupus erythematosus and Sjogren's syndrome. In addition, maternal anti-Ro and anti-La antibodies are highly associated with complete congenital heart block in neonates. The Ro RNPs consist of a 60 kilodalton protein (and possibly additional proteins) that bind one of several small RNA molecules of about 100 nucleotides in length. Although these particles appear to be components of all vertebrate cells, their subcellular location is controversial, and their function is unknown. A subset of the Ro RNPs also binds the La protein, a 50 kd phosphoprotein that binds all known RNA polymerase III transcripts early in their biogenesis. Although the La protein has been suggested to be required for transcription termination by RNA polymerase III, it is possible that this protein functions in some other aspect of the biogenesis of polymerase III RNAs. Like the Ro RNPs, the La protein has been detected in a wide variety of vertebrate cells. In addition, proteins with similar biochemical characteristics as the mammalian La protein have been detected in nematodes and yeast. The ubiquitous distribution and apparent conservation of the Ro RNPs and the La protein argue that they are important components of eukaryotic cells. The first aim of this proposal is to definitively determine the subcellular location of the Ro RNPs using antibodies and nucleic acid probes. The second objective is to identify molecules that interact with Ro RNPs using psoralen and UV-cross-linking and co-immunoprecipitation with anti-Ro antibodies. The third aim is to identify Ro RNPs and the La protein in organisms that will allow a genetic approach to function. The identification of homologues of the Ro RNPs and the La protein in either Drosophila, nematodes or yeast will allow us to assess the consequences of genetically depleting these components from cells and organisms and to genetically identify factors that interact with Ro RNPs and the La protein. Determination of the functions of these conserved cellular components will expand our knowledge of basic cellular processes and may also provide clues to why these particles are frequent targets of the immune response in certain autoimmune diseases.