Molecular Analysis of Uniparental Inheritance of Chloroplast DNA in Chlamydomonas Reinhardtii

细胞器（线粒体和叶绿体）DNA的单代遗传（UP）发生在整个真核生物王国，但尚未在任何物种中对其机制进行完整的分子描述。土壤藻类莱茵衣藻（Chlamydomonas reinhardtii）叶绿体染色体的UP遗传与大多数动物的线粒体DNA遗传有一个惊人的特征：亲本一方（藻类中的负交配型，动物中的雄性）的细胞器DNA被核酸酶活性特异性地破坏，这意味着另一方（正交配型，雌性）的细胞器DNA必须受到核酸酶的保护。本项目将评估C. reinhardtii中一个候选保护蛋白Otu2和一个候选破坏蛋白TatD1，以及另外两个蛋白Ezy1和Ezy2，这两个蛋白显然促进了它们在受精卵中的活性。方法将包括免疫定位和在配子和受精卵中敲低和错误表达这些蛋白质对UP的影响。由于Otu2同源物在去泛素化途径中具有特征，并且具有线粒体靶向序列的TatD1核酸酶被认为在细胞凋亡中发挥作用，因此这些研究可能具有超出UP理解的影响。这个项目有望为为什么细胞器（线粒体和叶绿体）DNA只通过一个亲本传递以及这是如何实现的问题提供长期寻求的答案。这样的理解对植物和动物的育种计划可能是重要的，其中细胞器不相容可能导致育种失败。致力于提高公众的科学素养，研究者广泛从事教师培训和成人教育等领域。此外，她还将招收本科生实习生。

Uniparental (UP) inheritance of organellar (mitochondrial and chloroplast) DNA occurs throughout the eukaryotic kingdom, but there is as yet no complete molecular description of its mechanism in any species. UP inheritance of chloroplast chromosomes in the soil alga Chlamydomonas reinhardtii shares a striking feature with mitochondrial DNA inheritance in most animals: the organellar DNA of one parent (the minus mating type in the alga, the male in animals) is specifically destroyed by nuclease activity, meaning that the organellar DNA of the other parent (plus, female) must be protected from the nuclease. This project will evaluate a candidate protector protein, Otu2, and a candidate destroyer, TatD1, in C. reinhardtii as well as two other proteins, Ezy1 and Ezy2, that apparently facilitate their activities in the zygote. Approaches will include immunolocalization and the effects on UP of knocking down and mis-expressing these proteins in gametes and zygotes. Since Otu2 orthologs feature in deubiquination pathways, and TatD1 nucleases with mitochondrial targeting sequences are posited to play a role in apoptosis, these studies may have an impact beyond an understanding of UP.This project promises to provide long-sought answers to the questions of why organellar (mitochondrial and chloroplast) DNA is only transmitted through one parent, and how this is accomplished. Such understanding is likely to be important to plant and animal breeding programs wherein organellar incompatibilities may contribute to breeding failures. Committed to increasing the public's scientific literacy, the investigator engages extensively in such areas as teacher training and adult education. In addition, she will recruit undergraduate trainees.