Translation and its regulation in different compartments of the plant cell

虽然大多数其他真核生物具有移动性，但植物已经进化出专门的适应机制来对动态环境做出反应。最基本的适应过程之一是基因表达的快速调节，在植物中，这是在mRNA翻译成蛋白质的水平上高度调节的。到目前为止，蛋白质生物合成的结构和机制研究主要是在细菌系统中进行的，最近在低等真核生物(酵母)和哺乳动物中进行。相比之下，有关植物翻译的知识却很少。在植物细胞中，蛋白质合成发生在三个不同的区域：细胞质、叶绿体和线粒体。这些细胞隔间中的每一个都有一个专门的翻译设备，具有不同的组成。为了了解植物翻译的特异性和多样性，特别是为植物不同细胞室中专门的翻译调控机制提供结构基础，本建议旨在利用高分辨率低温电子显微镜(Cryo-EM)解决从细胞质中主动翻译植物核糖体和处于全面功能状态的叶绿体的结构。在一种综合的方法中，这些结构研究将得到质谱学和核糖体图谱分析的补充，以高分辨率产生对植物在生理条件下的翻译调控机制的跨学科观点。这一点非常重要，因为植物蛋白质生产的调节对于不同生态系统和农业环境中的发展、环境可塑性和生物量产量至关重要。

While most other eukaryotes have mobility, plants have evolved specialized adaptive mechanisms to respond to a dynamic environment. One of the most fundamental adaptation processes is the rapid regulation of gene expression, which in plants is highly modulated at the level of mRNA translation into protein. Thus far, structural and mechanistic studies of protein biosynthesis have been mainly conducted in the bacterial system, and more recently in lower eukaryotes (yeast) and mammals. By comparison, knowledge about translation in plants is sparse. In the plant cell, protein synthesis takes place in three different compartments: cytosol, chloroplast, and mitochondria. Each of these cell compartments has a specialized translation apparatus with a distinct composition. In order to understand the specificity and diversity of translation in plants, and particularly to provide the structural foundation for specialized translational control mechanisms in different plant cell compartments, this proposal aims to solve the structures of actively translating plant ribosomes derived from cytosol as well as chloroplast in comprehensive functional states using high-resolution cryo-electron microscopy (cryo-EM). In an integrative approach, these structural studies will be complemented by mass spectrometry and ribosome profiling analyses to generate an interdisciplinary view of plant translation regulation mechanisms in physiologic conditions at high-resolution. This is of a high importance, as the modulation of protein production in plants is critical for development, environmental plasticity, and biomass yield in diverse ecosystems and agricultural settings.