Control of Gene Expression in the Biosynthesis of Mitochondrial Ribosomes

尽管核糖体在原核细胞和真核细胞中具有普遍性， 细胞，我们对它们的结构，功能 通过几十年的深入研究， 细菌核糖体，主要在E.杆菌 相比 细菌，真核细胞维持着明显不同的 核糖体用于细胞质、叶绿体和 线粒体 一个重要的研究目标是了解 代表特殊适应的真核核糖体特征 复杂的基因组组织和亚细胞区室化 真核细胞的基因。 酿酒酵母是一种 用于细胞器和细胞外基质分析的实验系统 单个细胞内的细胞质核糖体。 几个实验室 正在研究酵母细胞质核糖体，我们的目标是为 关于酵母线粒体核糖体的补充信息， 他们的选民。 线粒体的主要功能 酵母中的翻译系统是产生少量的 内分泌细胞能量转换复合物的亚基 膜的 为了完成这项任务，核线粒体 基因用于编码所需的RNA和蛋白质， 翻译器 除了其中一种蛋白质外， 小核糖体亚基（VAR 1），所有的核糖体蛋白都是 由60-70个不同的核基因编码。 在这四个基因中 由我们表征的MRP 7和MRP 20特别有趣 因为它们编码与EL 27和EL 23相关的蛋白质 蛋白质，分别为E. coli 50 S核糖体亚基。两 MRP和MRP 20是酵母中的必需蛋白质， 实验证据表明，EL 27和 E.大肠杆菌核糖体。 E23是一个 一级rRNA结合蛋白，也可能位于 肽转移酶中心。 本研究的目的 建议是基于这样的论点，即MRP 7和MRP 20， 它们的细菌对应物，很可能接近于 核糖体的重要催化中心。 我们打算用一个 结合分子遗传学和生物化学方法：1）获得 关于合成、结构和功能的其他信息 MRP 7和MRP 20或两者。 该研究将提供新的 深入了解蛋白质的结构和功能， 位于核糖体的高度保守的功能域中。

Despite the universality of ribosomes in procaryotic and eucaryotic cells, the majority of our knowledge of their structure, function and synthesis has been developed through decades of intensive study of bacterial ribosomes, predominantly in E. coli. In contrast to bacteria, eucaryotic cell maintain distinctly different sets of ribosomes for protein synthesis in cytoplasm, chloroplasts, and mitochondria. An important research objective is to understand the features of eucaryotic ribosomes that represent special adaptations to complex genomic organization and subcellular comparmentalization for eucaryotic cells. The yeast Saccharomyces cerevisiae is a fertile experimental system for the analysis of both organellar and cytoplasmic ribosomes within a single cell. Several laboratories are studying yeast cytoplasmic ribosomes, our goal is to contribute complementary information about yeast mitochondrial ribosomes and their constituents. The principal function of the mitochondrial translation system in yeast is to produce a small number of subunits for the energy-transducing complexes of the inner membrane. To accomplish this task, both the nuclear mitochondrial genes are used to encode the requisite RNAs and proteins of the translational apparatus. With the exception of one protein of the small ribosomal subunit (VAR1), all of the ribosomal proteins are encoded by 60-70 different nuclear genes. Of the four such genes characterized by us MRP7 and MRP20 are particularly intriguing because they encode proteins that are related to the EL27 and EL23 proteins, respectively, of the E. coli 50S ribosomal subunit. Both MRP& and MRP20 are essential proteins in yeast, and there is strong experimental evidence for close physical proximity between EL27 and the peptidyltransferase center of the E. coli ribosome. EL23 is a primary rRNA binding protein, which may also be located near the peptidvltransferase center. The research objectives of this proposal are based on the contention that MRP7 and MRP20, like their bacterial counterparts, are likely to be close to an important catalytic center of the ribosome. We intend to use a combined molecular genetic and biochemical approach to : 1) gain additional information about the synthesis, structure, and function of the MRP7 and MRP20 or both. The research will provide new insight into the structure and function of proteins that are located in a highly conserved functional domain of the ribosome.