Structure and Physical Properties of RNA

描述（由申请人提供）：本申请寻求支持的主要活动是通过核磁共振和x射线晶体学确定生理上重要的rna的结构。最终目的是对所研究的rna的生物学特性进行化学理解。由于rna在基因表达中起着关键作用，因此所寻求的知识对于我们理解对包括人类在内的所有生物体至关重要的过程至关重要。要研究的两个具体问题是：细菌中核糖体蛋白合成的调控，以及真核生物中核糖体RNA转录物的假尿嘧啶化。在细菌中，核糖体蛋白的合成在翻译水平上受到依赖于特定核糖体蛋白和编码它们的mrna序列之间相互作用的机制的反馈调节，其中许多是多顺反子的。两个这样的系统是直接关注spc操纵子/S8系统和L10操纵子。/L10系统，但时间允许，其他将进行调查；例如，α操纵子/L4系统。对每个核糖体蛋白操纵子的调控至关重要的mRNA序列将尽可能精确地确定。将获得这些RNA序列和与之结合的核糖体蛋白之间形成的复合物的结构。在这些结构的基础上制定的关于翻译抑制机制的假设，然后将进行生物化学测试。由于细菌调节核糖体蛋白合成的机制不同于真核生物，因此可以想象，将会发现特异性抑制细菌生长的新方法。要研究的第二个问题是由在高等生物中负责伪尿嘧啶化rRNA转录物的boxH/ACA snoRNP系统提出的。据推测，这些snRNPs的RNA成分与rRNA转录本中的序列相互作用，这在文献中是没有先例的。将进行生化实验以确定假设的RNA/RNA相互作用是否可能，并将获得snoRNA的结构，无论是否有适当的rRNA序列结合。

DESCRIPTION (provided by applicant): The principle activity for which this application seeks support is determination of the structures of physiologically important RNAs by NMR and X-ray crystallography. The ultimate objective is a chemical understanding of the biological properties of the RNAs studied. Since RNAs play critical roles in gene expression, the knowledge sought is fundamental to our understanding of processes vital to all organisms, including humans. Two specific problems are to be investigated: the regulation of ribosomal protein synthesis in bacteria, and the pseudouridylation of ribosomal RNA transcripts in eukaryotes. In bacteria, ribosomal protein synthesis is feed-back regulated at the translational level by mechanisms that depend on interactions between specific ribosomal proteins and sequences within the mRNAs that encode them, many of which are polycistronic. The two such systems of immediate concern are the spc operon/S8 system, and L10 operon./L10 system, but time permitting, others will be investigates; e.g. the alpha operon/L4 system. The mRNA sequence critical for the regulation of each ribosomal protein operon will be determined as precisely as possible. Structures will be obtained of the complexes that form between these RNA sequences and the ribosomal proteins that bind to them. Hypotheses about the mechanism of translational repression, formulated on the basis of those structures, will then be tested biochemically. Since bacteria regulate ribosomal protein synthesis by mechanisms unlike those used by eukaryotes, it is conceivable that new ways of specifically inhibiting bacterial growth will be revealed. The second problem to be investigated is posed by the boxH/ACA snoRNP system responsible for pseudouridylating rRNA transcripts in higher organisms. The RNA components of these snRNPs are postulated to interact with sequences in rRNA transcripts in a way that has no precedent in the literature. Biochemical experiments will be done to determine whether RNA/RNA interactions of the sort hypothesized are possible, and structures will be obtained for a snoRNA, with and without an appropriate rRNA sequence bound.