FUNCTION OF THE RO RIBONUCLEOPROTEINS AND THE LA PROTEIN

该项目的总体目标是确定两个机构的职能， 保守的细胞成分，Ro核糖核蛋白颗粒（RNP） 和La蛋白质。 这两种细胞成分是常见的目标 系统性红斑狼疮患者的自身免疫反应 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 RNP由60千道尔顿的蛋白质组成（并且可能是 额外的蛋白质）结合多种小RNA分子之一 大约100个核苷酸长。 虽然这些粒子看起来 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，其功能不明。 Ro RNP的子集 也结合La蛋白，一种50 kd的磷蛋白，结合所有已知的 RNA聚合酶III在其生物发生的早期转录。 虽然 La蛋白被认为是转录所必需的 RNA聚合酶III终止，这种蛋白质可能 在聚合酶III RNA的生物发生的一些其他方面起作用。 与Ro RNP一样，La蛋白已在各种各样的细胞中检测到。 脊椎动物细胞 此外，具有类似生物化学性质的蛋白质 哺乳动物La蛋白的特性已被检测到， 线虫和酵母。 Ro RNP的普遍分布和明显的保守性， La蛋白认为它们是真核生物 细胞 本提案的第一个目的是明确确定 使用抗体和核酸的Ro RNP的亚细胞定位 probes. 第二个目标是识别与之相互作用的分子。 使用蛋白酶和UV交联和免疫共沉淀的Ro RNP 与抗Ro抗体。 第三个目标是确定Ro RNP和 La蛋白质在生物体中，将允许一种遗传方法的功能。 RNP和La蛋白同源物的鉴定 无论是果蝇、线虫还是酵母，都能让我们评估 从细胞中遗传消耗这些成分的后果， 生物体和基因识别与Ro RNP相互作用的因子 和La蛋白质。 确定这些保守的功能 细胞成分将扩展我们对基本细胞过程的知识 这也可能为为什么这些粒子是常见的目标提供线索 在某些自身免疫性疾病中的免疫反应。

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.