The RNA Degradosome: Functional Consequences of Enzyme Association on RNA Metabolism

对基因表达的基本理解需要了解从DNA基因组传递信息的信使RNA转录物的生命周期。解释这个生命周期的结束是具有挑战性的，因为多种细胞酶可能通过独立或组合作用来控制转录本的分解。该项目的总体目标是通过分析来自大肠杆菌的多酶RNA降解复合物来确定酶结合对RNA转录物分解的影响。大肠杆菌中称为“降解体”。降解体主要是核糖核酸内切酶RNase E、核糖核酸外切酶PNase和RNA解旋酶RhlB加上糖酵解酶烯醇化酶的组装体，其在RNA代谢中没有已知的作用。充分理解降解体功能的一个主要障碍是确定烯醇化酶在复合物中的作用。第一个目标是解决是否烯醇化酶有助于转录解体，可能通过协调RNA和能量代谢。第二个目的是确定降解体缔合对单个组分酶的影响。RhlB将被用作模型来描述解旋酶在底物和蛋白质结合后可以经历的结构和功能改变。这将鉴定可能导致链分离机制的构象变化和RhlB与降解体相互作用的后果。最终目的是通过解释野生型细胞和不能组装降解体的突变细胞之间观察到的表型差异的分子基础来辨别降解体组装的细胞益处。来自科学领域代表性不足或背景不利的群体的学生将作为研究团队的积极成员参加该项目。

Fundamental understanding of gene expression requires knowing the life cycle of messenger RNA transcripts that transmit information from the DNA genome. Explaining the end of this life cycle is challenging because multiple cellular enzymes may govern transcript disassembly through independent or combinatorial actions. The overall project goal is to define consequences of enzyme association on RNA transcript disassembly through analysis of a multi-enzyme RNA degrading complex from E. coli called the "degradosome". Degradosomes are mainly assemblies of endoribonuclease RNase E, exoribonuclease PNPase, and RNA helicase RhlB, plus the glycolytic enzyme enolase, which has no known role in RNA metabolism. A major obstacle to fully understanding degradosome function is defining the role enolase plays in the complex. The first aim is to resolve whether enolase contributes to transcript disassembly, possibly through coordination of RNA and energy metabolism. The second aim is to determine the impact of degradosome association on individual component enzymes. RhlB will be employed as a model to describe structural and functional alterations helicase enzymes can undergo upon substrate and protein binding. This will identify both the conformational changes likely responsible for the strand separation mechanism and the consequences of RhlB interaction with degradosomes. The final aim is to discern cellular benefits of degradosome assembly by explaining the molecular basis for a phenotypic difference observed between wild-type cells and mutant cells unable to assemble degradosomes. Students from groups underrepresented in science, or of disadvantaged background, will participate in the project as active members of the research team.