RNA protection and decay in yeast mitochondria

描述(申请人提供)：线粒体的功能需要在细胞核和细胞器基因组中编码的蛋白质的协调合成。这项研究的长期目标是了解线粒体基因表达是如何调控的。重点放在酵母核基因的子集上，编码进入细胞器参与转录后过程的蛋白质。七个线粒体mRNAs中的每一个都需要几个信息特异的因子来调节内含子的去除、mRNA的稳定性和翻译。对CBPL进行了深入的研究。它是细胞色素b基因稳定所必需的。最近，CBPL被发现是一个大型多亚单位复合体的一部分。CBS2是一种特异性促进COB翻译的因子，也存在于一个类似质量的大型复合体中。具体目的1是分析这些大分子复合体在RNA保护和翻译中的组成和功能。具体目标2是确定CBPL的两个功能--消息稳定和翻译--是否可以分开。具体目的3是研究Aep3在ATP8/6mRNA的保护和翻译中的作用。除了对保护mRNAs并促进其翻译的消息特异性因素的研究外，几个一般因素在mRNAs的周转中也是重要的。Cbt1蛋白的过度表达抑制了mRNA的不稳定性，而CBT1基因的缺失会导致前体RNA的加工缺陷。另外三种线粒体蛋白也与这些加工事件和mRNA的周转有关。Cbt1是一个由500,000道尔顿的蛋白质组成的大型复合体。具体目标4是分析这个大型复合体在前体RNA加工和mRNA周转中的组成和功能。这项工作将进一步加深我们对线粒体中RNA表达的总体理解。许多人类疾病是由调控线粒体基因表达的核基因突变引起的。酵母是了解人类线粒体疾病综合征中可能受到影响的过程的一个很好的模型系统。

DESCRIPTION (provided by applicant): Mitochondrial function requires the coordinate synthesis of proteins encoded in the nucleus and the organellar genome. The long-term goal of this research is to understand how mitochondrial gene expression is regulated. The focus is on the subset of yeast nuclear genes encoding proteins that enter the organelle to participate in post-transcriptional processes. Each of the seven mitochondrial mRNAs require several message-specific factors that regulate intron removal, mRNA stability and translation. Cbpl has been studied in-depth. It is required specifically for cytochrome b mRNA stability. Recently Cbpl was found to be part of a large multisubunit complex. Cbs2, a factor that specifically promotes translation of COB, is also in a large complex of similar mass. Specific Aim 1 is to analyze the composition and function of these large complexes in RNA protection and translation. Specific Aim 2 is to determine if the two functions of Cbpl, message stabilization and translation, are separable. Specific Aim 3 is to characterize Aep3 in its roles in protection and translation of ATP8/6 mRNA. In addition to the studies on message-specific factors that protect mRNAs and promote their translation, several general factors are important in the turnover of the mRNAs. Overexpression of the Cbt1 protein suppresses mRNA instability, whereas deletion of the CBT1 gene results in defective processing of precursor RNAs. Three other mitochondrial proteins have been implicated in these processing events and mRNA turnover. Cbt1 is in a large complex of proteins of 500,000 daltons. Specific Aim 4 is to analyze the composition and function of this large complex in precursor RNA processing and mRNA turnover. This work will further our general understanding of RNA expression in mitochondria. Many human diseases are caused by mutations in nuclear genes that regulate mitochondrial gene expression. Yeast is a good model system to understand processes that may be affected in human mitochondrial disease syndromes.