Control of Organelle Inheritance

小行星9319595 这项研究将为莱茵衣藻细胞器DNA的单亲遗传机制提供详细的分子理解。 C.质体基因组的单亲遗传。reinhardtii涉及两个事件：由交配型加（MT+）配子对合子贡献的染色体的保护，以及合子中未保护的MT-染色体的核酸酶破坏。 一个克隆的基因簇ezy-1与两个mt基因座相连，已经被这个实验室证明与破坏有关。 设计使用天然和/或重组ezy-1蛋白的实验以了解ezy-1是作为核酸酶还是作为核酸酶活性的激活剂起作用。 遗传和生物化学实验将确定保护是否直接赋予mt+叶绿体DNA（例如通过甲基化）或通过与该DNA相关的蛋白质。 最后，寻找并分析保护缺陷的插入突变株。 真核生物是由含有细胞器的细胞组成的。 其中，线粒体（动物和植物）和叶绿体（仅植物）含有它们自己的DNA互补物，来自它们作为自由生活的细菌的进化起源。 在有性生殖过程中，细胞器DNA总是只通过一个父母传递给后代，通常是通过母亲的卵子。 在单细胞衣原体中，两个亲本配子都向受精卵贡献等量的细胞器DNA，但其中一组随后被破坏。 该实验室已经克隆了一个基因，其蛋白质产物似乎参与了叶绿体DNA的选择性降解。 该项目建议通过遗传、分子和细胞生物学实验来测试这一推断，目标是了解一组亲本DNA是如何被破坏的，而另一组DNA是如何被保存在单个细胞中的。 ***

9319595 Goodenough The research proposed would provide detailed molecular understanding of the mechanisms of uniparental inheritance of organelle DNA in Chlamydomonas reinhardtii. Uniparental inheritance of the plastid genome in C. reinhardtii involved two events: protection of the chromosome contributed to the zygote by the mating-type plus (mt+) gamete, and nuclease destruction of the unprotected mt- chromosome in the zygote. A cloned gene cluster, ezy-1 linked to both mt loci, has been shown by this lab to be involved in destruction. Experiments using native and/or recombinant ezy-1 protein are designed to learn whether ezy-1 functions as the nuclease or as an activator of nuclease activity. Genetic and biochemical experiments will determine whether protection is conferred directly on the mt+ chloroplast DNA (e.g. via methylation) or via protein(s) that associate with this DNA. And finally, insertional mutant strains defective in protection will be sought and analyzed. %%% Eukaryotic organisms are composed of cells that contain organelles. Of these, mitochondria (animals and plants) and chloroplast (plants only) contain their own complements of DNA, derived from their evolutionary origin as free-living bacteria. During sexual reproduction, organelle DNA is invariably transmitted to offspring via only one parent, usually via the maternal egg. In the unicellular alga Chlamydomonas, both parental gametes contribute equal amounts of organelle DNA to the zygote, but one set is then destroyed. The lab has cloned a gene whose protein product appears to participate in this selective degradation of chloroplast DNA. The project proposes to test this inference via genetic, molecular, and cell biology experiments, the goal being to learn how one parental set of DNA is destroyed and the other is preserved within a single cell. ***