Transfer of Organelle Genes to the Nucleus

描述（申请人的摘要）细胞器基因的研究对于 我们对真核细胞和分子生物学的理解。正确的 真核细胞中细胞器的功能涉及精确的合作 核遗传系统和细胞器遗传系统之间。此功能的缺陷 对人类健康产生直接影响，这一点从强烈的 对线粒体遗传疾病的兴趣。本次活动的首要目标 该提案旨在解决遗传协同进化中的一个基本问题 真核细胞：细胞器基因如何功能性转移到真核细胞 进化过程中的核心，以及进化的节奏、模式和后果是什么 这些基因重定位？所有这些工作都是在植物中进行的，这对于 有几个原因应被视为研究功能性基因转移的模型 从细胞器到细胞核。 我们建议：1）使用DNA杂交阵列调查20,000个物种 植物以阐明损失的精细节奏和模式（以及 线粒体基因和内含子的增益），并使用这些发现作为 下面概述的许多更深入研究的起点； 2）测试， 对于几个线粒体基因，假设它们有许多单独的损失 反映功能性基因向细胞核转移的比率非常高，并且 在此过程中，更多地了解功能性基因转移的机制； 3） 深入研究一些基因转移案例以表征 跨区室复制的中间阶段，以确定其 线粒体与核基因丢失的持久性和动态 沉默，并调查跨区重复是否曾经发生过 固定的； 4) 识别持续基因转移率高的植物 并检验这一假设，即这是由反向率过高引起的 转录； 5）确定线粒体基因组是否重新获得基因 通过转移到细胞核而丢失，如果是这样，这是否是通过直接发生的 从同一生物体的细胞核返回，或从一个生物体的横向转移 不相关的生物体；和。我们的次要目标是确定起源和 一种极具侵入性的遗传因素的传播模式 - a 我们证明归巢组 I 内含子已侵入线粒体 coxi 基因超过 近期通过海量横向转账1000次 被子植物的进化。

DESCRIPTION (Applicant's Abstract) The study of organelle genes is essential to our understanding of eukaryotic cellular and molecular biology. The proper functioning of organelles in eukaryotic cells involves a precise cooperation between nuclear and organellar genetic systems. Defects in this functioning have direct consequences for human health, as is evident from the intense interest in mitochondrially-inherited diseases. The primary goal of this proposal is to address a fundamental problem in the genetic coevolution of the eukaryotic cell: How are organelle genes functionally transferred to the nucleus during evolution, and what are the tempo, pattern, and consequences of these genetic relocations? All of this work is carried out in plants, which for several reasons should be viewed as a model to study functional gene transfer from organelles to nucleus. We propose to: 1) use DNA hybridization arrays to survey 20,000 species of plants in order to elucidate the fine-scale tempo and pattern of loss (and gain) of mitochondrial genes and introns, and to use these findings as the starting point for many of the more in-depth studies outlined below; 2) test, for several mitochondrial genes, the hypothesis that their many separate losses reflect remarkably high rates of functional gene transfer to the nucleus, and in so doing, to learn more about the mechanisms of functional gene transfer; 3) examine a few cases of gene transfer in-depth in order to characterize intermediate stages of transcompartmental duplication, to determine their persistence and the dynamics of mitochondrial vs. nuclear gene loss and silencing, and to investigate whether transcompartmental duplications are ever fixed; 4) identify plants with highly elevated rates of ongoing gene transfer and test the hypothesis that this is caused by highly elevated rates of reverse transcription; 5) determine whether mitochondrial genomes ever reacquire genes lost through transfer to the nucleus, and if so, whether this occurs by direct return from the nucleus of the same organism, or by lateral transfer from an unrelated organism; and. Our secondary goal is to determine the origin and pattern of transmission of an extraordinarily invasive genetic element - a homing group I intron that we showed has invaded mitochondrial coxi genes over 1,000 times through a massive wave of lateral transfers during recent angiosperm evolution.