Arabidopsis 2010: Function of the Arabidopsis Small RNAs

该项目的目标是确定一类新发现的拟南芥调控分子--小RNA的生物学功能。小RNA通常含有20-25个核苷酸，很可能是由dsRNA特异的RNaseIII类机制产生的。最近，在拟南芥中发现了125个小RNA。其中一些来自已知或预测的蛋白质编码基因和转座子的序列。然而，绝大多数来自传统基因之间的基因间序列。拟南芥的小RNA类似于线虫中与RNA沉默相关的小干扰RNA(SiRNAs)和与翻译控制相关的小时间RNA(StRNAs)。这些拟南芥RNA被认为通过几种机制发挥功能，包括RNA沉默、翻译干扰和细胞核内的表观遗传机制，从而对基因和mRNA活性进行转录后调控。将使用不同的组织制备新的小RNA文库，组装小RNA信息数据库，并将小RNA序列存入GenBank(www.ncbi.nlm.nih.gov)。来自蛋白质编码基因的小RNA在转录后RNA沉默中的功能，以及来自基因间区的小RNA在核DNA的翻译控制和修饰中的功能将被确定。最后，将分析9个RNaseIII类蛋白在小RNA生物合成中的作用。结果将在同行评议的期刊、国际拟南芥研究会议和小RNA信息数据库上共享。该数据库将包括搜索小RNA图谱位置的能力、最近基因的信息、给定基因是否靠近小RNA以及其他互动特征和结果，科学界将通过网络访问该数据库(www.cgrb.orst.edu/carrington/mall RNAs)。可公开访问的小RNA信息数据库将产生广泛的影响，为研究人员提供有关感兴趣基因附近或内部的小RNA的信息，并允许随后进行基于小RNA的拟南芥基因组调控作用的实验。基因由许多不同的机制控制。最近，一种涉及一类不寻常的小RNA分子的新型调控系统被发现。小RNA被认为是通过与特定基因靶标的信使RNA结合来发挥功能的。然后，小的RNA会触发信使RNA的裂解，或者抑制它所结合的信使RNA的功能。该项目将导致发现新类型的小RNA分子，并确定这些调控因子如何影响模式植物拟南芥的基因表达。

The goal of this project is to determine the biological functions of a newly recognized class of Arabidopsis regulatory molecules - the small RNAs. The small RNAs typically contain 20-25 nucleotides and are likely generated by a dsRNA-specific, RNaseIII-like mechanism. Recently, 125 small RNAs were identified in Arabidopsis. Several arise from sequences in known or predicted protein-coding genes and transposons. The vast majority, however, arise from intergenic sequences between conventional genes. The Arabidopsis small RNAs resemble small interfering RNAs (siRNAs) associated with RNA silencing and small temporal RNAs (stRNAs) associated with translational control in C. elegans. These Arabidopsis RNAs are proposed to function in posttranscriptional regulation of gene and mRNA activity by several mechanisms, including RNA silencing, translational interference and epigenetic mechanisms in the nucleus. New libraries of small RNAs will be prepared using different tissues, a database of small RNA information will be assembled, and the small RNA sequences will be deposited into GenBank (www.ncbi.nlm.nih.gov). The function of small RNAs from protein-coding genes in posttranscriptional RNA silencing, and the function of small RNAs from intergenic regions in translational control and modification of nuclear DNA will be determined. Finally, the roles of each of nine RNaseIII-like proteins in small RNA biosynthesis will be analyzed. Results will be shared in peer-reviewed journals, at the International Conference on Arabidopsis Research, and on a database of small RNA information. The database, which will include capabilities for searching small RNA map positions, information about nearest genes, whether or not a given gene is near a small RNA, and other interactive features and results, will be made web-accessible to the scientific community (www.cgrb.orst.edu/carrington/smallRNAs). The publicly accessible database of small RNA information will have broad impact by providing researchers with information about small RNAs near or within genes of interest and allowing subsequent experiments on the roles of small RNA-based regulation of the Arabidopsis genome. Genes are controlled by many different mechanisms. Recently, a new type of regulatory system involving an unusual class of small RNA molecules was discovered. The small RNAs are proposed to function by binding to messenger RNA from specific gene targets. The small RNA would then trigger either cleavage of messenger RNA or inhibit the function of the messenger RNA to which it is bound. This project will result in discovery of new types of small RNA molecules and determine how these regulators affect gene expression in the model plant, Arabidopsis thaliana.