Novel mechanisms of plant mitochondrial DNA repair

植物线粒体DNA修复的新机制

• 批准号: 1413152
• 负责人: Alan Christensen
• 金额: $ 57.38万
• 依托单位: University of Nebraska-Lincoln
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-08-01 至 2019-10-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1413152&HistoricalAwards=false
• 关键词: Novel; mechanisms; plant; mitochondrial; DNA

The goal of this project is to provide fundamental knowledge of the energy conversion centers of plants that will allow scientists to engineer more energy efficient agricultural crops. The energy conversion centers or "powerhouses" of plant cells are called mitochondria, which are small membrane-bound compartments where the energy from carbon compounds is converted into a form that plant cells can use. Mitochondria have their own DNA, which is easily damaged and must be repaired to maintain efficient energy output. This project seeks to define the mechanism by which important gene sequences in mitochondrial DNA are repaired so that the efficient output of energy is maintained for plant growth. This project also seeks to provide training opportunities for graduate, undergraduate and high-school students, and to increase the diversity of students who are receiving research training.Plant mitochondrial genomes are notorious for their large and variable size, high rearrangement rates and low mutation rates. How coding sequences are highly conserved while the rest of the genome expands and rearranges is a mystery. Recent work suggests a model that the expansions and rearrangements are produced by error-prone repair mechanisms while genes are repaired very accurately. Plant mitochondrial genome rearrangements and repair errors lead to life-history trait changes such as male sterility, and our understanding of basic mechanisms of repair is currently inadequate for modeling and prediction of these processes and their outcomes. The central hypothesis of this project is that much of the DNA damage in mitochondria is processed through the various subtypes of double-strand break repair, leading to accurate repair of genes by gene conversion and repair of non-genes by inaccurate mechanisms including break-induced replication and non-homologous end-joining. This hypothesis will be tested by altering the repair pathways such that mismatches or double-strand breaks are created at known positions within the Arabidopsis thaliana mitochondrial genome, both in coding and noncoding DNA, and assessing which repair pathways have been used. This will lead to better understanding of the mechanisms and pathways of DNA repair and recombination in plant mitochondria. This work will also advance our knowledge of the mechanisms and theoretical underpinnings of evolutionary change in the mitochondrial genome. In addition, this project will provide training opportunities for graduate, undergraduate and high-school students from diverse backgrounds.

该项目的目标是提供有关植物能量转换中心的基础知识，使科学家能够设计出更节能的农业作物。植物细胞的能量转换中心或“发电站”被称为线粒体，这是一种结合在膜上的小隔间，碳化合物的能量在这里被转化为植物细胞可以使用的形式。线粒体有自己的DNA，很容易损坏，必须修复才能保持有效的能量输出。这个项目试图确定修复线粒体DNA中重要基因序列的机制，以保持植物生长所需的有效能量输出。该项目还寻求为研究生、本科生和高中生提供培训机会，并增加接受研究培训的学生的多样性。植物线粒体基因组以其大而可变的大小、高重组率和低突变率而臭名昭著。编码序列是如何高度保守的，而基因组的其余部分却在扩张和重排，这是一个谜。最近的工作提出了一个模型，即基因的扩张和重排是由容易出错的修复机制产生的，而基因被非常准确地修复。植物线粒体基因组重排和修复错误会导致雄性不育等生活史性状的变化，目前我们对修复的基本机制的了解不足以对这些过程及其结果进行建模和预测。该项目的中心假设是，线粒体中的大部分DNA损伤是通过不同亚型的双链断裂修复来处理的，通过基因转换导致基因的准确修复，以及通过不准确的机制修复非基因，包括断裂诱导的复制和非同源末端连接。这一假说将通过改变修复途径来检验，从而在拟南芥线粒体基因组中的已知位置产生错配或双链断裂，无论是编码还是非编码DNA，并评估使用了哪些修复途径。这将有助于更好地了解植物线粒体DNA修复和重组的机制和途径。这项工作还将促进我们对线粒体基因组进化变化的机制和理论基础的了解。此外，该项目还将为不同背景的研究生、本科生和高中生提供培训机会。