Structural Biology of RNA Splicing

RNA剪接的结构生物学

基本信息

批准号：
9068978
负责人：
Navtej Singh Toor
金额：
$ 29.45万
依托单位：
UNIVERSITY OF CALIFORNIA, SAN DIEGO
依托单位国家：
美国
项目类别：
财政年份：
2012
资助国家：
美国
起止时间：
2012-07-16 至 2018-05-31
项目状态：
已结题

项目摘要

DESCRIPTION (provided by applicant): PROJECT SUMMARY/ABSTRACT Structural biology of RNA splicing. RNA splicing is a fundamental biological mechanism essential for the survival of every eukaryotic organism. It involves the excision of non-coding introns from pre-messenger RNAs and ligation of the adjacent exons to generate mature mRNA for translation by the ribosome. Spliceosomal introns comprise ~30% of the human genome and there is relatively little known about the precise structural details of their mechanism of excision catalyzed by the spliceosome. Group II introns are considered to be the ancestors of spliceosomal introns, therefore we are using the group II intron as a tractable model system to gain detailed molecular insight into eukaryotic splicing. Previously, the PI worked to determine the first crystal structure of a group II intron. This structure revealed that introns splice via a two-metal ion mechanism. However, this structure was of a hydrolytic, linear group II intron that was missing an important region called domain 6. This crucial domain contains the bulged adenosine responsible for forming the branched RNA known as a lariat. The lariat consists of an unusual 2'-5' phosphodiester bond between the ribose sugar of the bulged adenosine and the 5' end of the intron. The analogous motif in spliceosomal introns is called the branch site. Mutations in the branch site lead to defects in lariat formation that are the cause of several human diseases. Lariat formation is essential for proper splice site selection by the spliceosome and is considered to be a characteristic hallmark of eukaryotic splicing. Our long-term goal is to gain knowledge of eukaryotic splicing mechanisms by studying a lariat-forming group II intron. We will use biochemical and structural approaches to: 1) Determine the structural basis for lariat formation. 2) Analyze catalytic intermediates in the splicing pathway to determine the conformational changes that are associated with the progression of splicing. This is expected to have direct parallels with RNA splicing catalyzed by the spliceosome in eukaryotes.

描述（由申请人提供）：项目摘要/摘要 RNA 剪接的结构生物学。 RNA剪接是每个真核生物生存所必需的基本生物机制。它涉及从前信使 RNA 中切除非编码内含子并连接相邻的外显子以生成成熟的 mRNA 供核糖体翻译。剪接体内含子约占人类基因组的 30%，但人们对其剪接体催化的切除机制的精确结构细节知之甚少。 II组内含子被认为是剪接体内含子的祖先，因此我们使用II组内含子作为易于处理的模型系统来获得对真核剪接的详细分子洞察。此前，PI 致力于确定 II 族内含子的第一个晶体结构。这种结构揭示了内含子通过两种金属离子机制进行剪接。然而，该结构是一个水解的线性 II 族内含子，缺少一个称为结构域 6 的重要区域。这个关键结构域包含凸起的腺苷，负责形成称为套索的分支 RNA。套索由凸出的腺苷的核糖和内含子的 5' 末端之间不寻常的 2'-5' 磷酸二酯键组成。剪接体内含子中的类似基序称为分支位点。分支位点的突变会导致套索形成缺陷，从而导致多种人类疾病。套索的形成对于剪接体选择正确的剪接位点至关重要，并且被认为是真核剪接的特征标志。我们的长期目标是通过研究形成套索的第二组内含子来获得真核剪接机制的知识。我们将使用生化和结构方法来： 1) 确定套索形成的结构基础。 2) 分析剪接途径中的催化中间体，以确定与剪接进展相关的构象变化。预计这与真核生物中剪接体催化的RNA剪接有直接相似之处。

项目成果

期刊论文数量（4）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Structure determination of group II introns.

DOI：
10.1016/j.ymeth.2017.06.020
发表时间：
2017-08-01
期刊：
Methods (San Diego, Calif.)
影响因子：
0
作者：
Wiryaman T;Toor N
通讯作者：
Toor N

Crystal structure of a group II intron in the pre-catalytic state.

DOI：
10.1038/nsmb.2270
发表时间：
2012-04-08
期刊：
NATURE STRUCTURAL & MOLECULAR BIOLOGY
影响因子：
16.8
作者：
Chan, Russell T.;Robart, Aaron R.;Rajashankar, Kanagalaghatta R.;Pyle, Anna Marie;Toor, Navtej
通讯作者：
Toor, Navtej

Identification of a GUAAY Pentaloop Sequence Involved in a Novel RNA Loop-Helix Interaction.

鉴定参与新型 RNA 环-螺旋相互作用的 GUAAY 五环序列。