STRUCTURAL STUDIES OF THE RIBOSOMAL PROTEIN S15

肿瘤发生和癌变的机制基础涉及基因表达的异常调控。RNA：蛋白质相互作用对所有水平的基因表达(如转录、剪接和翻译)都很重要。作为研究RNA：蛋白质相互作用的模型系统，威廉姆森团队正在研究一种与16S核糖体RNA结合的核糖体蛋白S15的复合体。S15蛋白只是组装30S核糖体颗粒所需的主要核糖体结合蛋白之一。核糖体蛋白S15也通过与自己的信使RNA的5‘-非翻译区(5’-UTR)结合来调节自己的表达，从而减少S15蛋白的翻译。本项目的总体目标是了解这个5‘-UTRmRNA：S15复合体特定相互作用的结构基础。从S15的5‘-UTRmRNA结合位点的生化特征开始，可以准备一个最小的结合位点用于进一步的核磁共振光谱研究。为了帮助核磁共振结构的阐明，将合成特定的同位素标记的核糖核苷酸，从而简化核磁共振谱。对这个5‘-UTRmRNA：S15复合体的研究将与实验室中已经在进行的16S rRNA：S15复合体的研究形成对比。这项研究具有重要意义，原因有三。1)我们将扩展关于RNA的常识：蛋白质识别。2)将学习有关导致S15识别两个看似不同的RNA的特定相互作用和构象变化的细节。3)将开发新的工具和策略，以研究富含生物的大型多组分络合物。

The mechanistic basis of neoplasia and carcinogenesis involves abnormal regulation of gene expression. RNA: protein interactions are important for all levels of gene expression (e.g. transcription, splicing, and translation). As a model system for studying RNA:protein interactions, the Williamson group is studying a complex of ribosomal protein S15 bound to 16S ribosomal RNA. The S15 protein is just one of the primary ribosomal binding proteins required for the assembly of the 30S ribosomal particle. The ribosomal protein S15 also regulates its own expression by binding to the 5'-untranslated region (5'-UTR) of its own messenger RNA and, consequently, reducing translation of S15 protein. The overall goal of this project is to understand the structural basis for the specific interactions of this 5'-UTR mRNA:S15 complex. Beginning with biochemical characterization of the 5'-UTR mRNA binding site for S15, a minimal site can be prepared for further study by NMR spectroscopy. Aiding in the NMR structure elucidation, specifically isotopically labeled ribonucleotides will be synthesized, thus simplifying the NMR spectra. The study of this 5'-UTR mRNA:S15 complex will provide contrast to studies of the 16S rRNA:S15 complex already underway in the lab. This research is significant for three reasons. 1) We will extend general knowledge about RNA:protein recognition. 2) Details about the particular interactions and conformation changes responsible for S15 recognition of two seemingly dissimilar RNAs will be learned. 3) New tools and strategies will be developed directed toward the study of large multicomponent complexes abundant in biology.