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。 的 在所有真核细胞中，细胞器的正常功能都涉及到 细胞核和细胞器遗传学之间的精确合作 系统. 这一建议涉及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研究中进行研究。 假设的新家-核心-在他们的模式， 表达和靶向其产物回到 叶绿体 我们将研究两个新的假设， 分散的重复序列，假定的转座因子， 存在于三叶草和天竺葵的叶绿体基因组中， 从细胞核侵入这些基因组。 几个叶绿体 最近进入线粒体基因组的假基因 以其交易方式和交易性质为特征， 所涉及的中间分子。 最后，研究将测试 假设大多数植物线粒体基因组来自 从原子核中分离出来。 第二，内部重排（倒置和换位） 细胞器基因组内将检查如何， 以及它们如何影响基因功能。 的假设 最近，对三叶草和大白菜的叶绿体基因组进行了研究， 不稳定的入侵重复，pupressible转座， 元素将通过检查这些重复的作用进行测试， 产生特定的和最近的重排。 的影响 这些重组对叶绿体基因功能的影响 也要检查。 植物的不稳定性 线粒体基因组将继续探索使用 芸苔属物种的大基因组作为模式系统。 这些研究将涉及对以下终点进行测序： 重新排列以了解它们是如何产生的， 根据线粒体DNA重排的动力学， 细胞培养和从融合的原生质体再生的植物中。 一 主要重点将是基因重排和破坏， 与线粒体功能障碍相关结构和功能 在两个雄性不育的芸苔属细胞质中。

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.