ORGANIZATION AND EXPRESSION OF ORGANELLE GENOMES

细胞器基因组和基因的研究对我们的 了解真核细胞和分子生物学。这个 所有真核细胞中细胞器的正常功能涉及 细胞核与细胞器遗传的精确配合 系统。这项建议解决了两个相互关联的问题 细胞器分子遗传学。 第一，DNA交换的机制和后果 将探索细胞基因组之间的序列。两个基因 已经离开叶绿体基因组的基因将在他们的 假定的新家园-核心-在他们的模式方面 表达和他们产品的目标回溯到 叶绿体。我们将调查两部小说的假设 分散的重复序列家族，假定的转座元件， 居住在三叶草和天竺葵叶绿体基因组中的 从细胞核入侵了这些基因组。几个叶绿体 最近进入线粒体基因组的假基因将 以其交换方式和性质为特征 涉及到的中间分子。最后，研究将测试 认为大多数植物线粒体基因组都是由 来自原子核。 第二，内部重新安排(反转和换位) 在细胞器内，基因组将通过它们是如何 以及它们如何影响基因功能。这一假设认为 三叶草和天竺葵叶绿体基因组是最近研究的 因反复入侵而变得不稳定，被认为是可转位的， 元素将通过检查这些重复项在 产生了具体的和最近的重新安排。其影响 在这些重排中适当的叶绿体基因功能将 也要接受检查。植物的异常不稳定 线粒体基因组将继续使用 适宜大小的十字花科植物基因组作为模式系统。 这些研究将涉及对 重新安排以了解它们是如何生成的，以及 根据线粒体DNA重排的动态变化 细胞培养和从融合原生质体再生的植物中。一个 主要焦点将放在基因重排和破坏上。 与线粒体功能障碍相关的结构和功能 在两个雄性不育的油菜细胞质中。

The study of organelle genomes and genes is essential to our understanding of eukaryotic cellular and molecular biology. The proper functioning of organelles in all eukaryotic cells involves a precise cooperation between nuclear and organelle genetic systems. This proposal addresses two interconnected problems in organelle molecular genetics. First, mechanisms and consequences of the exchange of DNA sequences between cellular genomes will be explored. Two genes that have departed the chloroplast genome will be studied in their putative new home - the nucleus - in terms of their mode of expression and the targeting of their products back to the chloroplast. We will investigate the hypothesis that two novel families of dispersed repeats, putative transposable elements, residing in the chloroplast genomes of clover and geranium have invaded these genomes from the nucleus. Several chloroplast pseudogenes that recently entered the mitochondrial genome will be characterized as to their mode of exchange and the nature of the intermediate molecules involved. Finally, studies will test the hypothesis that most of the plant mitochondrial genome is derived from the nucleus. Second, internal rearrangements (inversions and transpositions) within organelle genomes will be examined in terms of how they occur and how they affect gene function. The hypothesis that the chloroplast genomes of clover and geranium were recently destabilized by invading repeated, putatively transposable, elements will be tested by examining the role of these repeats in generating specific and very recent rearrangements. The effects of these rearrangements on proper chloroplast gene function will also be examined. The extraordinary instability of plant mitochondrial genomes will continue to be explored using the convenient-sized genomes of Brassica species as a model system. These studies will involve sequencing the endpoints of rearrangements to understand how they are generated, and following the dynamics of mitochondrial DNA rearrangement in cell culture and in plants regenerated from fused protoplasts. A major focus will be on rearrangements and disruptions in gene structure and function associated with mitochondrial dysfunction in two male-sterile Brassica cytoplasms.