Gene-specific and General RNA Regulators in Chloroplasts

叶绿体中基因特异性和通用 RNA 调节因子

• 批准号: 0646350
• 负责人: David Stern
• 金额: $ 42.58万
• 依托单位: Boyce Thompson Institute Plant Research
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-09-01 至 2011-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0646350&HistoricalAwards=false
• 关键词: Gene; specific; General; RNA; Regulators

Chloroplast gene expression is essential for photosynthesis, and has to be coordinated with the nuclear genome. This coordination is achieved by a suite of mostly post-transcriptional regulators, some of which have recognizable prokaryotic origins, and others of which appear to have been uniquely derived following endosymbiosis. A fascinating and largely unresolved question is how these proteins of very different origins interact to effect both gene-specific and general control of chloroplast gene expression. This project uses the green alga Chlamydomonas reinhardtii as a model to explore the relationship between two regulatory proteins, MCD1 and MCD4. MCD1 encodes a large, novel protein which appears to be a member of a multimeric complex, and is specifically required for accumulation of the chloroplast petD mRNA, which it protects from ribonucleolytic decay through interaction with the petD 5' untranslated region. MCD4 was isolated in a suppressor screen of strains carrying petD 5' UTR mutations which destabilize the transcript, however the mcd4 suppressor proved to be pleiotropic, displaying numerous defects in other chloroplast transcripts. The specific aims of this research are to: (1) explore the biochemical activities of the MCD1 protein through in vitro RNA-binding assays, to determine if it has properties which can account for its specificity for petD; (2) purify the multiprotein complex containing MCD1, and determine its components; (3) identify the pleiotropic gene MCD4; and (4) study the specificity and interactions of MCD4 with other RNA metabolic factors using genetic crosses, in particular two candidate ribonucleases which it might regulate, polynucleotide phosphorylase and RNase J1.This project explores an example of how plant cells have evolved to coordinate activities in different compartments. The chloroplast, where photosynthesis occurs, was captured in ancient times as a bacterium. In this project, two genes located in the nucleus are under study, since they regulate chloroplast genes, originally inherited with the bacterium, which are required for photosynthesis. The research will offer opportunities for future scientists, either as summer interns or university undergraduates, to gain valuable experience and taste the excitement of biological research. Underrepresented groups have been prominent among these interns in past years. The leader of this project is also involved in educating the lay public about plant science, through the radio program MicrobeWorld, a Science Cabaret, and other vehicles.

叶绿体基因表达对于光合作用至关重要，必须与核基因组协调。这种协调是通过一套主要的转录后调节剂来实现的，其中一些具有可识别的脑质性起源，而另一些则似乎是内共生杂志后独特得出的。一个引人入胜且在很大程度上尚未解决的问题是，这些起源截然不同的蛋白如何相互作用，以实现叶绿体基因表达的基因特异性和一般控制。该项目使用绿色的藻类衣原体Reinhardtii作为探索两种调节蛋白MCD1和MCD4之间关系的模型。 MCD1编码一种大型新型蛋白质，该蛋白似乎是多聚体复合物的成员，并且是叶绿体PETD mRNA的聚集所需的，它可以通过与PETD 5'未翻译区域相互作用来保护叶绿体PETD mRNA。 MCD4在带有PETD 5'UTR突变的菌株的抑制剂筛选中分离出来，这些突变破坏了转录物的稳定，但是MCD4抑制剂被证明是多效性的，在其他叶绿体转录本中表现出许多缺陷。这项研究的具体目的是：（1）通过体外RNA结合测定法探索MCD1蛋白的生化活性，以确定其是否具有其特性，可以说明其对PETD的特异性； （2）纯化包含MCD1的多蛋白络合物，并确定其成分； （3）识别多效基因MCD4； （4）研究MCD4使用遗传杂交的特异性和相互作用与其他RNA代谢因子的相互作用，特别是它可能调节的两个候选核糖核酸酶，多核苷酸磷酸化酶和RNase J1。该项目探讨了植物细胞如何在不同隔间中配置植物细胞如何在不同隔室中配置活性的示例。光合作用发生的叶绿体在古代被捕获为细菌。在该项目中，正在研究核中的两个基因，因为它们调节最初用细菌遗传的叶绿体基因，这是光合作用所需的。这项研究将为未来的科学家（作为暑期实习生还是大学大学生）提供机会，以获得宝贵的经验并品尝生物学研究的兴奋。在过去几年中，这些实习生中代表性不足的群体在这些团体中一直是突出的。该项目的领导者还参与了通过无线电计划Microbeworld，Acience Cabaret和其他车辆对植物科学进行教育。