Quality control of gene expression - RNA surveillance

基因表达的质量控制 - RNA 监测

• 批准号: BB/F010281/1
• 负责人: Helen Saibil
• 金额: $ 19.54万
• 依托单位: Birkbeck, University of London
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2008
• 资助国家: 英国
• 起止时间: 2008 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=BB%2FF010281%2F1
• 关键词: Quality; control; gene; expression; RNA

The exosome is a large multisubunit complex endowed with exonuclease activity. This nuclease is the major 3'-5' exonuclease of eukaryotic cells. It is constituted of a core containing 10 different proteins to which associate nuclear and cytoplasmic specific subunits. The exosome has been implicated in most decay pathways involved in the removal of aberrant and non-functional RNA molecules. Those include elimination of Cryptic Unstable Transcrips (CUTs), aberrant tRNAs, non-spliced pre-mRNA as well as some snRNAs and rRNAs in the nucleus. In the cytoplasm, the exosome has been show to degrade non-functional mRNAs containing a premature stop codon (NMD), those lacking a stop codon (NSD) or those provoking ribosome stalling (No-Go decay). The exosome thus plays a central and essential role in the control of RNA quality. The exosome has to target and degrade aberrant RNAs without attacking functional molecules. This discrimination results in part from the action of factors that will bind and/or modify biologically relevant substrates and target them to degradation. Such factors include the Trf/Air poly(A) polymerase and Mtr4 DEAD box helicase in the nucleus and the Ski7 GTpase and Ski2/3/8 complex in the cytoplasm. If the enzymes and factors involved in these pathways are known, the mechanisms leading them to selectively degrade aberrant RNA molecules remain unclear. We propose here a multidisciplinary study of the role of the exosome in RNA quality control pathways. This analysis will combine molecular biology and biochemical approaches, native mass spectrometry, structural analyses by electron microscopy and small angle X-ray scattering to provide a structural and functional framework allowing the understanding of the role of the exosome in RNA surveillance. We envision that the methodology, developed in this collaborative project involving experts in complementary fields, will be useful to study other RNA based processes and other molecular mechanisms in the future.

外泌体是一种具有外切核酸酶活性的大型多育复合物。该核酸酶是真核细胞的主要3'-5'外切酶。它由一个核心构成，该核心包含10种不同的蛋白质，与核和细胞质特异性亚基相关联。外泌体与大多数衰减途径有关，与异常和非功能性RNA分子的去除。其中包括消除神秘的不稳定转trips（切割），异常TRNA，未切割的前MRNA以及细胞核中的某些SNRNA和RRNA。在细胞质中，已经显示出外泌体可以降解含有过早终止密码子（NMD）的非功能mRNA，缺乏终止密码子（NSD）或那些引发核糖体停滞（无腐烂）的mRNA。因此，外泌体在控制RNA质量中起着核心和重要作用。外泌体必须靶向和降解异常的RNA，而无需攻击功能分子。这种歧视部分源于将结合和/或修改生物学相关的底物并将其靶向降解的因素的作用。这些因素包括细胞核中的TRF/空气聚（A）聚合酶和MTR4 Dead Box解旋酶，SKI7 GTPase和SKI2/3/8复合物中的SKI2/8复合物。如果已知这些途径中涉及的酶和因素，则导致它们有选择性降解异常RNA分子的机制尚不清楚。我们在这里提出了一项多学科研究，介绍了外泌体在RNA质量控制途径中的作用。该分析将结合分子生物学和生化方法，天然质谱法，通过电子显微镜和小角度X射线散射进行结构分析，以提供一个结构和功能框架，从而了解外壳在RNA监测中的作用。我们设想，该方法在这个涉及互补领域专家的协作项目中开发的方法将对未来研究其他基于RNA的过程和其他分子机制有用。

项目成果

Newly folded substrates inside the molecular cage of the HtrA chaperone DegQ.

• DOI: 10.1038/nsmb.2210
• 发表时间: 2012-01-15
• 期刊: NATURE STRUCTURAL & MOLECULAR BIOLOGY
• 影响因子: 16.8
• 作者: Malet, Helene;Canellas, Flavia;Sawa, Justyna;Yan, Jun;Thalassinos, Konstantinos;Ehrmann, Michael;Clausen, Tim;Saibil, Helen R.
• 通讯作者: Saibil, Helen R.

Structure of a type IV secretion system core complex.

• DOI: 10.1126/science.1166101
• 发表时间: 2009-01-09
• 期刊: Science (New York, N.Y.)
• 作者: Fronzes R;Schäfer E;Wang L;Saibil HR;Orlova EV;Waksman G
• 通讯作者: Waksman G