Molecular Mechanism of Chloroplast RNA Editing

叶绿体RNA编辑的分子机制

• 批准号: 0716888
• 负责人: Maureen Hanson
• 金额: $ 45万
• 依托单位: Cornell Univ - State: AWDS MADE PRIOR MAY 2010
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-09-15 至 2012-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0716888&HistoricalAwards=false
• 关键词: Molecular; Mechanism; Chloroplast; RNA; Editing

RNA editing is a form of RNA processing that occurs in diverse organisms. Editing is often essential for proper gene function and/or regulation. In vascular plants, mitochondrial and chloroplast RNAs are modified by C-to-U base modification. Editing sometimes creates start codons for plant organelle proteins, and is required to restore codons that specify highly conserved amino acids. RNA editing in plant organelles appears to be a correction mechanism to ameliorate T-to-C mutations that would otherwise prevent gene expression or result in non-functional proteins. Sequences surrounding C targets of RNA editing in chloroplasts are thought to be specifically recognized by proteins, perhaps recruiting other proteins involved in the enzymatic modification of C to U. The goal of this project is to identify unknown components of the chloroplast RNA editing apparatus. While cis-elements upstream of edited Cs have been identified, little is known about the trans-factors required to recognize the correct C and convert it to U. Efforts will be made to fractionate maize chloroplast extracts for partial purification of the editing apparatus, which will be subjected to mass spectrometry for protein identification. Candidate editing complex members will undergo functional analysis. A high-throughput assay for editing of all chloroplast editing sites in a species will be developed. RNA sequence requirements for binding of editing factors will be determined. Antisera to an editing factor protein will be used in purification schemes to identify components of the editing complex. A combination of biochemical and molecular genetic approaches should allow dissection of the molecular apparatus needed to convert Cs to Us in vascular plant chloroplasts. RNA editing is a fundamental biological process with profound effects on gene expression. Understanding how organelles in plants regulate this process may eventually result in applications that could improve agricultural productivity by increasing efficiency of energy acquisition and utilization by chloroplasts and mitochondria. This project will provide training in biochemistry, molecular biology, and genetics for several graduate students and undergraduates. Materials useful for laboratory exercises in plant cell structure and microscopy will be produced.

RNA编辑是RNA加工的一种形式，发生在不同的生物体中。编辑通常对于适当的基因功能和/或调节是必不可少的。 在维管植物中，线粒体和叶绿体RNA通过C-to-U碱基修饰而被修饰。编辑有时会为植物细胞器蛋白质创建起始密码子，并且需要恢复指定高度保守氨基酸的密码子。 植物细胞器中的RNA编辑似乎是一种纠正机制，以改善T到C突变，否则会阻止基因表达或导致非功能性蛋白质。叶绿体中RNA编辑的C靶标周围的序列被认为是被蛋白质特异性识别的，可能会招募参与C到U的酶促修饰的其他蛋白质。该项目的目标是确定叶绿体RNA编辑装置的未知组件。虽然已经鉴定了编辑的Cs上游的顺式元件，但对识别正确的C并将其转化为U所需的反式因子知之甚少。 将努力使玉米叶绿体提取物破碎以部分纯化编辑装置，其将经受质谱以进行蛋白质鉴定。候选编辑复合体成员将进行功能分析。将开发用于编辑物种中所有叶绿体编辑位点的高通量测定。将确定编辑因子结合的RNA序列要求。编辑因子蛋白的抗血清将用于纯化方案以鉴定编辑复合物的组分。生物化学和分子遗传学的方法相结合，应允许解剖的分子装置需要转换Cs到我们在维管植物叶绿体。 RNA编辑是一个基本的生物学过程，对基因表达有着深远的影响。了解植物中的细胞器如何调节这一过程，最终可能会导致通过提高叶绿体和线粒体的能量获取和利用效率来提高农业生产力的应用。本计画将提供生物化学、分子生物学及遗传学之训练给数位研究生及本科生。将制作对植物细胞结构和显微镜实验室练习有用的材料。