NMR STUDIES OF RNA/RNA INTERACTION FOR THE BIMOLECULAR TRANSCRIPTION REGULATIO

本子项目是利用由NIH/NCRR资助的中心赠款提供的资源的众多研究子项目之一。子项目和研究者（PI）可能已经从另一个NIH来源获得了主要资金，因此可以在其他CRISP条目中表示。列出的机构是中心的，不一定是研究者的机构。病毒使用一套不同的机制来转录调节蛋白质表达。一种最新颖的转录调控机制是在双链病毒的单链RNA基因组中发现的。RNA-2编码区的20个核苷酸元件和外壳蛋白亚基因组mRNA启动子RNA-1的8个核苷酸元件之间的RNA-RNA相互作用已经被证实(1)。为了进一步用核磁共振波谱法表征这一机理，制备了一个短合成寡核苷酸模型体系。RNA-2的20mer类似物形成发夹环结构，通过热变性和核磁共振方法确定稳定的G:U碱基对闭合环：1。合成的双分子RNA-2和RNA-1复合物的动力学特性使其不适合用于高分辨率三维结构的测定2。dianthovirus序列保守性和NMR结果的结合提供了足以产生低分辨率模型的结构约束3。该模型的总体特征是两个螺旋区域，一个是RNA-2发夹的茎部，另一个是RNA-2环与RNA-1碱基配对形成的螺旋。该络合物中有7个碱基对。该结构与假结的结构特征相似。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Viruses use a diverse set of mechanisms for transcriptional regulation of protein expression. One of the most novel transcription regulation mechanisms is found in the single stranded, bipartite RNA genomes of dianthoviruses. An RNA-RNA interaction between an 20 nucleotide element in the coding region of RNA-2 and an 8 nucleotide element of the coat protein subgenomic mRNA promoter RNA-1 has been previously demonstrated (1). To further characterize this mechanism by the NMR spectroscopy method, a model system of short synthetic oligonucleotides was prepared. The 20mer analog of RNA-2 forms a hairpin loop structure with a stable G:U basepair closing the loop as determined by thermal denaturation and NMR methods:1. The dynamics of the synthetic bi-molecular RNA-2 and RNA-1 complex make it unsuited for determination of a high resolution 3 dimensional structure2. The combination of dianthovirus sequence conservation and NMR results provide structural restrains sufficient to generate a low resolution model3. The general features of the model are two helical regions, the stem of the RNA-2 hairpin and a helix formed by the base pairing between the RNA-2 loop and RNA-1. Seven base pairs are present in the complex . The structure has similarity to the structural features of pseudoknots.