Plant mitochondrial gene expression and evolution

线粒体拥有自己独特的DNA，具有细胞能量产生所必需的基因。自从线粒体通过原始呼吸细菌和宿主细胞之间的共生而产生以来，它们进化出了非常不同的存储和解码遗传信息的方式。对植物、动物、真菌和原生生物线粒体的研究揭示了许多新的特征(如改变遗传密码、RNA编辑、可移动内含子核酶)，这促使人们重新考虑分子生物学中的某些基本原理。 我的研究项目集中在开花植物的线粒体遗传系统上，这是已知的最大和最具活力的线粒体DNA。从它们的基因复制的RNA在被解码为蛋白质之前必须经历复杂的事件(如编辑和反式剪接)。内含子的移除属于一个有趣的自剪接移动逆转录元件家族，涉及不寻常的剪接反应，我们正在使用分子、生化和生物信息学策略来了解所采取的机制和进化路径。我们还在研究小麦胚胎到幼苗发育过程中的RNA处理事件(在常温和低温生长下)，并对DNA重排对表达的影响特别感兴趣。在某些情况下，零散的基因片段仍然具有功能，因为RNA拷贝正确地拼接在一起，而在其他情况下，DNA重排已知会导致雄性不育的突变。后者对作物育种者在生产杂交种子方面很重要。 植物也提供了一个独特的机会来研究基因在进化过程中从线粒体到细胞核的成功移动，因为这些事件仍然在植物中发生。当我们追踪这种迁移所涉及的步骤时，我们发现了重复的基因、沉默的基因和假基因。这项工作旨在提供对植物细胞内不同遗传间隔如何相互通信的洞察，以及(基因操纵的)产品如何针对线粒体。

Mitochondria possess their own distinctive DNA, with genes essential for cellular energy production. Since the time that mitochondria arose through symbiosis between a primitive respiring bacterium and host cell, they have evolved very different ways of storing and decoding genetic information. The study of mitochondria from plants, animals, fungi and protists has uncovered a wealth of novel features (such as altered genetic codes, RNA editing, mobile intron ribozymes), and this has prompted a reconsideration of certain fundamental principles in molecular biology. My research program focuses on the mitochondrial genetic systems of flowering plants, which have the largest and most dynamic mitochondrial DNAs known. RNA copied from their genes must undergo complex events (such as editing and trans-splicing) before being decoded into protein. The removal of introns, which belong to an intriguing family of self-splicing mobile retroelements, involves unusual splicing reactions, and we are using molecular, biochemical and bioinformatics strategies to understand mechanistic and evolutionary pathways taken. We are also studying RNA processing events during embryo-to-seedling development (under ambient and cold growth) in wheat, an important Canadian crop plant, and have particular interest in the impact of DNA rearrangements on expression. In some cases, scattered pieces of genes are still functional because RNA copies are correctly spliced together, whereas in other cases, DNA rearrangements are known to lead to mutants which are male sterile. The latter are important to crop breeders in the production of hybrid seed. Plants also offer a unique opportunity to study the successful movement of genes from the mitochondrion to the nucleus during evolution, because these events are still going on in plants. As we trace the steps involved in such migration, we are finding duplicated genes, silent genes, and pseudogenes. This work is directed at providing insight into how the different genetic compartments inside the plant cell communicate with each other, as well as how (genetically-manipulated) products can be targeted to the mitochondrion.