Regulation of Mitochondrial DNA

***线粒体在细胞功能中的作用越来越被研究人员所认识。线粒体编码自己的基因组（mtDNA），这是一种对其功能至关重要的分子。尽管第一次描述是在50多年前，但关于mtDNA是如何维持和表达的许多问题仍然存在。作为一名研究线粒体调控基本机制的研究者，我新成立的项目将探索mtDNA调控。除了研究线粒体和mtDNA的传统方法外，我们将利用我们开发的新方法将DNA转染到线粒体中。利用我们在mtDNA和线粒体细胞生物学方面的专业知识，拟议的研究包括三个目标，总体目标是了解蛋白质和序列元件如何调节mtDNA。******目的1：确定如何控制mtDNA的平衡表达***三个线粒体启动子的相对转录率平衡线粒体基因表达，mtDNA复制和线粒体核糖体生物发生。我们将通过检查线粒体转录因子和mtDNA序列的作用来确定线粒体转录的相对速率是如何调节的。此外，我们将研究影响线粒体转录的信号通路如何改变线粒体表达的平衡，并确定改变这种平衡的功能后果。******目标2：测试mtDNA序列元件在细胞中的作用***我们将DNA转染到线粒体的新方法使我们首次能够测试mtDNA序列元件的细胞相关性。我们将不直接操纵mtDNA，这是目前不可能的，我们将转染含有mtDNA调控元件的质粒，它可以被改造。确定维持该质粒所需的结构元件将导致对mtDNA如何被调节的新理解。******目标3：揭示核转录因子在线粒体中的新作用***虽然已经报道了核转录因子（NTFs）在线粒体中的作用，但它们的作用在很大程度上仍未明确。NTFs是否在线粒体转录中起直接作用是一个有争议的问题，因为很难将它们的核功能和线粒体功能分开。我们将通过将这些转录因子直接靶向线粒体并确定它们对线粒体功能的影响来测试这个问题。******新颖性和意义***我们的研究是我们以前工作的延伸，将通过回答有关mtDNA调控的基本问题来推进我们对线粒体功能的基本理解。提高我们对线粒体的基本理解将在细胞和有机体水平上产生影响，也与动物健康有关。该研究项目还将为下一代线粒体研究人员提供培训场所。＊＊＊＊＊＊＊＊

***The role that mitochondria play in cellular function is increasingly being recognized by researchers. Mitochondria encode their own genome (mtDNA), a molecule that is essential for their function. Although first described over 50 years ago, many questions remain about how mtDNA is maintained and expressed. As a researcher studying the basic mechanisms regulating mitochondria, my newly established program will explore mtDNA regulation. In addition to traditional means of studying mitochondria and mtDNA, we will utilize novel methods we have developed to transfect DNA into mitochondria. Taking advantage of our expertise in mtDNA and mitochondrial cell biology, the proposed research comprises three aims with an overall goal of understanding how proteins and sequence elements regulate mtDNA. ******Aim 1: To determine how the balanced expression of mtDNA is controlled ***The relative rates of transcription from the three mitochondrial promoters balances mitochondrial gene expression, mtDNA replication, and mitochondrial ribosome biogenesis. We will determine how the relative rates of mitochondrial transcription are regulated by examining the roles of mitochondrial transcription factors and mtDNA sequences. Additionally, we will examine how signaling pathways affecting mitochondrial transcription alter the balance of mitochondrial expression and also determine the functional consequences of altering this balance. ******Aim 2: To test the role of mtDNA sequence elements in cells ***Our novel methods for transfecting DNA into mitochondria allow us for the first time to test the cellular relevance of mtDNA sequence elements. Instead of directly manipulating mtDNA, which is currently not possible, we will transfect a plasmid containing mtDNA regulatory elements, which can be engineered. Determining which structural elements are required for the maintenance of this plasmid will lead to novel understanding about how the mtDNA is regulated. ******Aim 3: To uncover novel roles of nuclear transcription factors in mitochondria ***While nuclear transcription factors (NTFs) have been reported in mitochondria, their roles remain largely undefined. Whether NTFs play a direct role in mitochondrial transcription is a matter of debate, as it is difficult to separate their nuclear and mitochondrial functions. We will test this issue by targeting these transcription factors directly to mitochondria and determining their effects on mitochondrial function. ******Novelty and Significance ***Our studies, which are an extension of our previously work, will advance our basic understanding of mitochondrial function by answering fundamental questions about the regulation of mtDNA. Improving our basic understanding of mitochondria will have an impact at both the cellular and organismal level and is also relevant to animal health. This research program will also provide a training venue for the next wave of mitochondrial researchers. ********