Deciphering the role of nuclear organization in mRNA and lncRNA nuclear retention

解读核组织在 mRNA 和 lncRNA 核保留中的作用

• 批准号: RGPIN-2020-06948
• 负责人: Zenklusen, Daniel
• 金额: $ 4.23万
• 依托单位: Université de Montréal
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2021
• 资助国家: 加拿大
• 起止时间: 2021-01-01 至 2022-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=741508
• 关键词: Deciphering; role; nuclear; organization; mRNA

The long-term objective of our research program is to develop and apply quantitative, single molecule and super-resolution microscopy RNA and protein imaging approaches, with the short-term objective to study the role of nuclear organization in modulating the selective nuclear retention of mRNAs and long-noncoding RNAs (lncRNAs). In eukaryotic cells, the site of genetic information storage is separated from the site of protein synthesis by packaging chromosomes in a separate cellular compartment, the nucleus. This separation required the co-evolution of a complex machinery that mediates the exchange of proteins and RNA between the two compartments. Within this regulatory framework, mRNA serves as a messenger molecule that, after synthesis in the nucleus, is transported to the cytoplasm for protein translation. In addition to mRNAs, eukaryotic genomes are transcribed into a vast variety of RNAs with little or no coding potential, the largest and possibly most diverse group of which is often summarized as lncRNAs. Most lncRNAs share many features with mRNAs, however, despite their similarities to mRNAs in terms of processing and composition, most lncRNAs are retained in the nucleus. Moreover, recent studies indicate that mRNAs can also be nuclear retained under certain conditions, suggesting that nuclear retention might be an important regulatory mechanism that modulates different aspects of gene expression; however, the mechanisms that modulate selective retention of lncRNAs and mRNAs are currently not understood. Sequestration within various nuclear compartments is thought to play a role in retention, yet, this process is not well studied and mechanistically ill defined. Our objective is therefore to develop and apply quantitative live-cell and single molecule microscopy approaches and assays that will allow us to study the mechanisms that mediate nuclear RNA retention and investigate the role of different nuclear compartments in this process. We hypothesize that different nuclear compartments modulate retention through different mechanisms. While retention in nuclear speckles (NP) may be a transient process that is mediated by frequent dynamic interactions of RNAs with NP components, allowing diffusion of molecules within and between NPs, retention in paraspeckles might be achieved by static retention facilitated by an RNA scaffold, enabling long term sequestration within a single paraspeckle. Completing this project will shed light onto the fundamental mechanisms of RNA retention and the role of different compartments in this process - a so far unappreciated and poorly studied aspect of gene regulation - leading to a better understanding of the underlying basic biology of gene expression. It will furthermore lead to the creation of quantitative tools to study RNA in cells that can be applied to investigate various aspects of RNA metabolism.

我们研究计划的长期目标是开发和应用定量、单分子和超分辨率显微镜 RNA 和蛋白质成像方法，短期目标是研究核组织在调节 mRNA 和长链非编码 RNA (lncRNA) 选择性核保留中的作用。在真核细胞中，通过将染色体包装在单独的细胞区室（细胞核）中，将遗传信息存储位点与蛋白质合成位点分开。这种分离需要复杂机制的共同进化，以介导两个区室之间蛋白质和 RNA 的交换。在这个调控框架内，mRNA充当信使分子，在细胞核中合成后，被转运到细胞质进行蛋白质翻译。除了 mRNA 之外，真核基因组还可以转录为多种几乎没有或没有编码潜力的 RNA，其中最大且可能最多样化的一组通常被概括为 lncRNA。大多数lncRNA与mRNA有许多共同特征，然而，尽管它们在加工和组成方面与mRNA相似，但大多数lncRNA都保留在细胞核中。此外，最近的研究表明，mRNA在某些条件下也可以被保留在核中，这表明核保留可能是调节基因表达不同方面的重要调节机制。然而，目前尚不清楚调节 lncRNA 和 mRNA 选择性保留的机制。人们认为各种核隔室中的隔离在保留中发挥着作用，然而，这一过程尚未得到充分研究，并且在机制上也没有明确定义。因此，我们的目标是开发和应用定量活细胞和单分子显微镜方法和测定，使我们能够研究介导核 RNA 保留的机制，并研究不同核区室在此过程中的作用。我们假设不同的核区室通过不同的机制调节保留。虽然核斑点 (NP) 中的保留可能是一个短暂的过程，由 RNA 与 NP 成分的频繁动态相互作用介导，从而允许 NP 内部和之间的分子扩散，但副斑点中的保留可能是通过 RNA 支架促进的静态保留来实现的，从而能够在单个副斑点内长期隔离。完成这个项目将揭示RNA保留的基本机制以及不同区室在此过程中的作用——这是基因调控的一个迄今为止未被重视和研究很少的方面——从而更好地理解基因表达的基础生物学。它还将进一步创建用于研究细胞中 RNA 的定量工具，这些工具可用于研究 RNA 代谢的各个方面。