Structure, function and evolution of small RNAs in unicellular eukaryotes

单细胞真核生物小RNA的结构、功能和进化

• 批准号: 355757-2013
• 负责人: Russell, Anthony
• 金额: $ 2.62万
• 依托单位: University of Lethbridge
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2018
• 资助国家: 加拿大
• 起止时间: 2018-01-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=663934
• 关键词: Structure; function; evolution; small; RNAs

Ribonucleic acid (RNA) molecules called non-coding RNAs (ncRNAs) have diverse functions, controlling a variety of cellular processes in all organisms. Many eukaryotic genomes contain more genomic DNA sequence specifying the production of ncRNAs than specifying proteins and yet, the detailed function of most of these ncRNAs remains unknown. Consequently, identifying and determining functions of ncRNAs is becoming an increasingly important area of functional genomics - relating genomic DNA sequence to biological function - and is a primary objective of my research program. We will study ncRNAs in the unicellular eukaryotes called protists, organisms that comprise the bulk of eukaryotic evolutionary diversity. Nobel prize-winning discoveries were the result of first characterizing ncRNAs and their cellular functions in protists, such as self-splicing (autocatalytic) introns and telomerase RNA, both first identified in Tetrahymena thermophila. Two main classes of ncRNAs that we will investigate are the small nucleolar (sno) and small nuclear (sn) RNAs. SnoRNAs are known to have a functional role in the synthesis of ribosomes - the complexes responsible for protein synthesis in the cell. We will use an in vivo approach to determine the specific roles of individual snoRNAs during ribosome synthesis in the protist Euglena gracilis, an organism with a particularly complex ribosome assembly pathway. SnRNAs are core components of the eukaryote-specific cellular structure(s) termed the spliceosome. Spliceosomes are required for the removal of intervening sequences (introns) from protein-coding RNAs, a process called splicing. We will characterize splicing and spliceosome components in the early-diverging protist Giardia lamblia. This organism is particularly interesting because it possesses a very unusual splicing system, contains relatively few introns, and appears to be undergoing intron loss as it reduces its genome size and further adapts to its parasitic lifestyle. We will also characterize gene expression pathways and cellular components used for ncRNA synthesis in these protists, and exploit their evolutionary positions to derive insights about ncRNA and spliceosome evolution in eukaryotes.

核糖核酸（RNA）分子称为非编码RNA（ncRNA），具有多种功能，控制所有生物体中的各种细胞过程。许多真核生物基因组含有更多的基因组DNA序列，指定的ncRNA的生产比指定的蛋白质，然而，这些ncRNA的详细功能大多数仍然未知。因此，识别和确定ncRNA的功能正在成为功能基因组学的一个越来越重要的领域-将基因组DNA序列与生物功能联系起来-并且是我研究计划的主要目标。我们将研究被称为原生生物的单细胞真核生物中的ncRNA，原生生物包括大部分真核生物进化多样性。获得诺贝尔奖的发现是第一次表征原生生物中的ncRNA及其细胞功能的结果，例如自剪接（自催化）内含子和端粒酶RNA，两者都是在嗜热四膜虫中首次发现的。我们将研究的两类主要ncRNA是小核仁（sno）和小核（sn）RNA。已知SnoRNA在核糖体的合成中具有功能性作用-核糖体是负责细胞中蛋白质合成的复合物。我们将使用一种体内方法来确定单个snoRNA在原生生物Euglena gracilis（一种具有特别复杂的核糖体组装途径的生物体）的核糖体合成过程中的特定作用。SnRNA是被称为剪接体的真核生物特异性细胞结构的核心组分。剪接体是从编码蛋白质的RNA中去除插入序列（内含子）所必需的，这一过程称为剪接。我们将在早期分歧的原生生物贾第鞭毛虫特点剪接和spliceosome组件。这种生物特别有趣，因为它拥有一个非常不寻常的剪接系统，包含相对较少的内含子，并且似乎正在经历内含子丢失，因为它减少了基因组大小并进一步适应其寄生生活方式。我们还将表征基因表达途径和用于ncRNA合成的细胞组分在这些原生生物，并利用其进化的立场，以获得有关ncRNA和剪接体在真核生物进化的见解。