Mechanisms of human RNA turnover and quality control

 描述（由申请人提供）：基因表达可以在多个水平进行调节，包括RNA稳定性。RNA的降解速率可以按数量级变化，并且mRNA的稳定性可以由细胞信号调节。此外，存在靶向异常RNA以快速降解的质量控制途径。RNA在其整个生命周期中存在于动态核糖核蛋白（RNP）复合物中，该复合物控制RNA的功能和命运。控制RNP动力学的机制知之甚少。随着理解RNP修饰和RNA调节中重塑的原则的长期目标，本研究的具体目标是理解，i）在炎症反应期间TTP如何调节mRNA衰变激活，ii）RNA解旋酶UPF1的ATP酶活性在无义介导的衰变（NMD）途径的靶与非靶mRNP上差异调节的机制，iii）人类去帽复合物如何重塑翻译起始机制以接近mRNA帽，iv）精氨酸甲基化和赖氨酸乙酰化在去腺苷化之后的去帽活化中的作用，以及v）3'末端加尾在snRNA代谢中的作用。这些问题将使用生物化学、基于人类细胞的和全球质谱和测序分析的组合来解决。对这些问题的研究将揭示RNP修饰和重塑在RNA调控中作用的新原理。RNA周转的控制对于基因表达的适当调节至关重要，其失调已被确定为多种人类疾病的原因或结果。本文描述的研究旨在了解人类细胞中RNP被修饰和重塑以控制RNA功能的机制。这应该为mRNA调控的机械原理提供基本的新见解，当放松调控时可能导致疾病。该提案中与疾病的具体联系包括炎症反应期间mRNA调控的研究，这对抑制炎症性疾病至关重要，以及与儿童神经系统疾病有关的去腺苷酸酶基因突变的研究。

 DESCRIPTION (provided by applicant): Gene expression can be regulated at multiple levels including RNA stability. The rate of degradation of RNAs can vary by orders of magnitude and the stability of mRNAs can be regulated by cellular cues. Moreover, quality control pathways exist that target aberrant RNAs for rapid degradation. RNAs exist throughout their lifetime in dynamic ribonucleoprotein (RNP) complexes, which control the function and fate of the RNA. The mechanisms that control RNP dynamics are poorly understood. With the long-term goal of understanding the principles that underlie RNP modification and remodeling in RNA regulation, the specific objectives of this research is to understand, i) how mRNA decay activation by TTP is regulated during the inflammatory response, ii) the mechanisms by which the ATPase activity of the RNA helicase UPF1 is differentially regulated on target versus non-target mRNPs of the nonsense-mediated decay (NMD) pathway, iii) how the human decapping complex remodels to the translation initiation machinery to access the mRNA cap, iv) the role of arginine methylation and lysine acetylation in activation of decapping subsequent to deadenylation, and v) the role of 3' end tailing in snRNA metabolism. These questions will be addressed using combinations of biochemical, human cell-based, and global mass spec and sequencing assays. Pursuing these questions should reveal new principles of the role of RNP modification and remodeling in RNA regulation. Relevance to Public Health The control of RNA turnover is critical for proper regulation of gene expression, and its misregulation has been identified as a cause or consequence of multiple human disorders. The studies described here are aimed at understanding the mechanisms by which RNPs in human cells are modified and remodeled to control RNA function. This should provide fundamental new insights into mechanistic principles of mRNA regulation, which when deregulated can lead to disease. Specific links to diseases in this proposal include the study of mRNA regulation during inflammatory responses, critical for inhibiting inflammatory diseases, and the study of mutations in a deadenylase gene that have been linked to a childhood neurological disorder.