Basis of gene regulation by a guanine-binding mRNA

描述（由申请人提供）：最近的发现揭示了一类广泛的序列基序，位于细菌mrna的5'非翻译区，它们具有在转录或翻译水平上调节基因表达的能力，以响应细胞内代谢物浓度。这些被称为核糖开关的RNA元件能够通过结合小分子（例如鸟嘌呤、赖氨酸或焦磷酸硫胺素）直接影响基因调控。在枯草芽孢杆菌中，这些RNA元件似乎控制了至少2%的所有基因的正确表达，这表明它们是细胞内重要的基本调控机制。为了了解这些元件如何控制鸟嘌呤核糖体开关配体复合物的基因表达晶体，该晶体衍射x射线的分辨率至少为2.9 a。利用x射线晶体学，这种结构以及相关的腺嘌呤响应元件将被确定，以确定RNA的特征，这些特征有助于配体结合的高亲和力和特异性，这将导致对代谢产物如何影响基因调控的一般理解。同时，将使用等温量热法（ITC）和一系列含有功能基团缺失的rna来探测配体识别的能量学。

DESCRIPTION (provided by applicant): Recent discoveries have revealed a broad class of sequence motifs located in the 5' untranslated region of bacterial mRNAs that have the ability to regulate gene expression at the level of either transcription or translation in response to intracellular metabolite concentrations. These RNA elements, dubbed riboswitches, are able to directly effect gene regulation by binding a small molecule (guanine, lysine or thiamine pyrophosphate, for example). In B. subtilis, these RNA elements appear to control the proper expression of at least 2% of all genes, suggesting that they are a fundamentally important regulatory mechanism within the cell. To understand how these elements control gene expression crystals of a guanine riboswitch-ligand complex that diffract X-rays to at least 2.9 A resolution have been obtained. Using X-ray crystallography, this structure, along with the related adenine-responsive element will be determined to define the features of the RNA that contribute to the high affinity and specificity of ligand binding which will lead to a general understanding of how gene regulation can be effected by metabolites. In parallel, the energetics of ligand recognition will be probed using isothermal calorimetry (ITC) and a series of RNAs that contain functional group deletions.