Mechanisms of gene-specific and genome-wide regulation of mRNA turnover

描述（由申请人提供）： 基因特异性和基因组范围内mRNA周转调控的机制真核基因表达调控的核心是转录本丰度的精确和快速调控。RNA水平由产生和降解的平衡决定，因此，不仅要检查转录，还要检查mRNA周转，以剖析控制基因表达的调控网络，并了解细胞反应的动力学。虽然已经了解了很多关于控制转录的机制，mRNA衰变对转录组形成的贡献仍然知之甚少。本研究的目的是阐明mRNA周转调节基因特异性和基因组范围内mRNA水平变化的机制，并了解mRNA衰变和转录如何协调以诱导转录组的快速变化。本提案中描述的实验利用了一种非侵入性的代谢标记方法，使我们能够非常精确地测量芽殖酵母中所有mRNA的衰变率。酵母提供了一个很好的模型系统来表征mRNA周转的调节，并且由于所研究的途径在物种间高度保守，因此从我们的研究中获得的任何机制见解将与包括人类在内的所有真核生物直接相关。我们提出了一个创新的生物化学，遗传学和细胞生物学方法的组合，以解决三个特定的目标：（1）阐明机制，诱导周转的特定群体的mRNA。(2)研究mRNA降解因子Dhh1的生理功能，并了解Dhh1如何控制翻译抑制和mRNA降解。(3)确定全基因组mRNA周转调节的机制。该项目将导致发现调节mRNA衰变的新分子途径，并为真核基因表达程序中对细胞和生物体生理学各个方面至关重要的重要步骤提供基本的新见解。此外，了解mRNA衰变的调节将使我们对这一过程在人类疾病中是如何被错误调节的有重要的了解。

DESCRIPTION (provided by applicant): Mechanisms of gene-specific and genome-wide regulation of mRNA turnover Central to the control of eukaryotic gene expression is the precise and rapid regulation of transcript abundance. RNA levels are determined by a balance of both production and degradation, and thus, it is critical to examine not only transcription but also mRNA turnover to dissect the regulatory networks that control gene expression and to understand the kinetics of the cellular response. Whereas much has been learned about the mechanisms controlling transcription, the contribution of mRNA decay to shaping the transcriptome remains poorly understood. The objective of this research proposal is to elucidate the mechanisms by which mRNA turnover regulates gene-specific and genome-wide changes in mRNA levels, and to understand how mRNA decay and transcription are coordinated to induce rapid changes in the transcriptome. The experiments described in this proposal take advantage of a non-invasive metabolic labeling approach that allows us to measure decay rates with great precision for all mRNAs in budding yeast. Yeast provides an excellent model system to characterize the regulation of mRNA turnover, and because the pathways under investigation are highly conserved across species, any mechanistic insights obtained from our studies will be directly relevant to all eukaryotes including humans. We propose a combination of innovative biochemical, genetic and cell biological approaches to address three specific aims: (1) To elucidate mechanisms that induce the turnover of specific groups of mRNAs. (2) To investigate the physiological function of the mRNA decay factor Dhh1 and to understand how Dhh1 controls translational repression and mRNA degradation. (3) To identify mechanisms of genome-wide mRNA turnover regulation. This project will lead to the discovery of novel molecular pathways that regulate mRNA decay and provide fundamental new insight into an important step in the eukaryotic gene expression program critical for all aspects of cellular and organismal physiology. Furthermore, understanding the regulation of mRNA decay will give us critical insight into how this process is misregulated in human disease.