Understanding mRNA Condensation and Its Role in Translational Control during Stress

项目概要/摘要 细胞如何动态控制其蛋白质组以应对压力是一个基本方面 了解生物体如何对不断变化的环境做出反应。的两个代表性特征 细胞应激反应，在真核生物中普遍保守，并响应各种 不同的有害环境条件是：1) 细胞保护性热休克蛋白的上调 2) RNA 和蛋白质的生物分子缩合成组装体。大多数翻译都被关闭了，而 参与应激反应的蛋白质被有效地产生。如何重新编程以利于翻译 人们对转录后热休克蛋白的产生知之甚少，但生物分子缩合已经 与翻译控制有关。基本问题未完全回答：1）哪些 mRNA 凝结在 对压力的反应？ 2) 哪些细胞机制负责 mRNA 浓缩？ 3）什么是 mRNA 浓缩与翻译控制的功能相关性？ 在此，我们展示了未发表的工作，测量了 > 5,000 个基因在温度期间的 mRNA 溶解度 通过生化沉淀和 RNA 测序来检测酿酒酵母中的应激。这些数据告知我们 假设阻断翻译起始会通过特异性结合触发 mRNA 的缩合 未知的蛋白质因子。我们还预测，应激期间 mRNA 凝结是一个适应性过程 有助于压力反应信息的优先翻译。为了检验这些假设，我们的目标是 证实阻断翻译起始会触发转录组范围内的 mRNA 凝结 单个信息水平，确定 mRNA 浓缩所需的蛋白质因子，并测试 应激期间翻译重编程中的 mRNA 凝结。测量溶解度的初步数据 天然 mRNA 和报告基因 mRNA 都支持阻断翻译起始会引发缩合。我们有 确定并将询问一组翻译启动因素作为候选人假定所需的 mRNA浓缩。我们将测试候选者是否需要进行mRNA缩合和测量 应激期间干扰 mRNA 凝结的翻译效应。 生物分子凝聚体与细胞 RNA 稳态密切相关，其功能障碍已 与包括阿尔茨海默病和帕金森病在内的多种神经退行性疾病的发病机制有关。 了解 mRNA 如何凝结以及凝结的功能作用可了解疾病发病机制 并可能为受影响者的未来治疗提供信息。

Project Summary/ Abstract How cells dynamically control their proteome in response to stress is a fundamental aspect of understanding how organisms are able to react to changing environments. Two representative features of the cellular stress response, which is universally conserved across eukarya and occurs in response to a variety of different noxious environmental conditions, are 1) the upregulation of the cytoprotective heat shock proteins and 2) biomolecular condensation of RNA and protein into assemblies. Most translation is shut down, while proteins involved in the stress response are efficiently produced. How translation is reprogrammed to favor heat shock protein production post-transcriptionally is poorly understood, but biomolecular condensation has been linked to translational control. Basic questions are incompletely answered: 1) Which mRNAs condense in response to stress? 2) What cellular mechanisms are responsible for mRNA condensation? And 3) What is the functional relevance of mRNA condensation to translational control? Herein, we present unpublished work measuring mRNA solubility of >5,000 genes during temperature stress in S. cerevisiae by biochemical sedimentation followed by RNA-Sequencing. These data inform our hypothesis that blocking translation initiation triggers condensation of an mRNA through specific binding by unknown protein factor(s). We also predict that mRNA condensation during stress is an adaptive process contributing to the preferential translation of stress response messages. To test these hypotheses, we aim to confirm that blocking translation initiation triggers mRNA condensation both on a transcriptome-wide and individual message level, to determine protein factors required for mRNA condensation, and to test the role of mRNA condensation in translational reprogramming during stress. Preliminary data measuring the solubility of both native and reporter mRNAs support that blocking translation initiation triggers condensation. We have identified and will interrogate a set of the translation initiation factors as candidates putatively required for mRNA condensation. We will test whether the candidates are required for mRNA condensation and measure the translational effect of perturbing mRNA condensation during stress. Biomolecular condensates are intimately related to cellular RNA homeostasis, and their dysfunction has been linked to the pathogenesis of several neurodegenerative diseases including Alzheimer's and Parkinson's. Knowledge of how mRNAs condense and the functional role of condensation informs disease pathogenesis and may inform future treatments for those affected.