The Nucleolar Detention Center: a Hub of Long Noncoding RNAs that Imprison Proteins During Stress

核仁滞留中心：一个长的非编码RNA中心，在应激过程中将蛋白质禁锢起来 NIGMS R01(R01GM115342)授权续订 项目摘要 细胞适应各种应激条件的能力在各种生理和生理环境中起着至关重要的作用。 病理环境，包括发育、癌症和神经疾病。在当前的赠款周期中，我们 报道了来自刺激特异性的应激诱导的低复杂性非编码RNA的令人惊讶的发现 核糖体基因间隔区(RIGSRNA)；历史上人类基因组的一个谜团区域 被斥为“垃圾”DNA。我们发现低复杂性的rIGSRNA激活了一种生理性的淀粉样变性。 将核仁转化为淀粉样体(A体)的程序：固定蛋白的分子监狱 处于淀粉样蛋白状态。这一相当不寻常的翻译后调控途径使细胞能够迅速和 可逆地在A小体中存储内源性蛋白质阵列并进入静止状态以响应严重的 对环境的侮辱。虽然许多无膜隔室被描述为液状(例如应力 颗粒、P小体、生殖细胞颗粒)，我们对A小体的发现为淀粉样变性提供了证据 从生理上将生物物质转变为类固体状态的过程。在这次拨款续期中，我们将 表明核糖体基因间隔区产生了一个低复杂性的大家族，在它们的 长度、二核苷酸含量和重复排列。RIGSRNA的这些可变属性的作用是 结构决定因素，招募共同和不同的蛋白质，以种子条件特定的A体。我们会 还提供了A小体包裹可能参与应激的多聚腺苷化RNA组的初步数据 恢复。从概念上讲，这项由NIGMS资助的研究揭示了一个依赖于类的适应性程序 可诱导的低复杂性RNA分子通过组装我们新发现的核来控制细胞命运 无膜细胞器：A小体。基于上述理由，我们假设“低” 复杂性rIGSRNA激活生理性淀粉样变性程序，组装应激特异的A-体“。在……里面 具体的目标是：1.发现rIGSRNA中的二核苷酸重复基序，它是A小体的种子；2.探索 赋予A-体同一性的机制；以及3.通过以下方式检查涉及多腺苷化RNA存储的过程 A形体。我们关于低复杂性rIGSRNA的拟议工作将开辟新的研究思路 在基因组中观察到的简单的长基因间二核苷酸重复的生理作用，但通常 忽略为不起作用的DNA/RNA。此外，观察到低复杂性RNA激活了一种 生理性液体向固体转化的淀粉样变过程将为病理研究提供新的视角 淀粉样蛋白的形成与许多人类疾病有关。最后，我们计划对多腺苷化RNA进行的实验 A-Body的储存将揭示RNA生物学中的新调控途径。我们的研究计划是一般性的。 科学家对核质结构、细胞应激反应、长非编码RNA的研究感兴趣 生物学和生理性/病理性淀粉样变。

The Nucleolar Detention Center: A Hub of Long Noncoding RNA that Imprison Proteins During Stress NIGMS R01 (R01GM115342) Grant Renewal Project Summary The ability of cells to adapt to a wide variety of stress conditions plays a critical role in various physiological and pathological settings, including development, cancer and neurological disorders. In this current grant cycle, we reported the surprising discovery of stress-induced low complexity noncoding RNA derived from stimuli-specific loci of the ribosomal intergenic spacer (rIGSRNA); an enigmatic region of the human genome historically dismissed as “junk” DNA. We showed that low complexity rIGSRNA activate a physiological amyloidogenic program that converts the nucleolus into Amyloid Bodies (A-bodies): a molecular prison of immobilized proteins in an amyloid-like state. This rather unusual post-translational regulatory pathway enables cells to rapidly and reversibly store an array of endogenous proteins in A-bodies and enter quiescence in response to severe environmental insults. While many membrane-less compartments have been described as liquid-like (e.g. stress granules, P-bodies, germ cell granules), our discovery of A-bodies provided evidence of an amyloidogenic process that can physiologically transition biological matter to a solid-like state. In this grant renewal, we will show that the ribosomal intergenic spacer produces a large family of low complexity RNA that differ in their length, dinucleotide content and repetitive arrangement. These variable properties of rIGSRNA operate as architectural determinants that recruit common and distinct proteins to seed condition-specific A-bodies. We will also provide preliminary data that A-bodies enclose groups of polyadenylated RNA that may be involved in stress recovery. Conceptually, this NIGMS-funded research has uncovered an adaptive program that relies on a class of inducible low complexity RNA molecules to control cellular fate by assembling our newly-discovered nuclear membrane-less organelle: A-bodies. Based on these aforementioned rationales, we hypothesize that “Low complexity rIGSRNA activate physiological amyloidogenic programs that assemble stress-specific A-bodies”. In the Specific Aims, we will: 1. Uncover dinucleotide repeat motifs in rIGSRNA that seed A-bodies; 2. Explore the mechanisms that confer A-body identity; and 3. Examine processes involved in polyadenylated RNA storage by A-bodies. Our proposed work on low complexity rIGSRNA will open new lines of investigation on the physiological role of simple long intergenic dinucleotide repeats observed across the genome, but commonly ignored as non-functional DNA/RNA. In addition, the observation that low complexity RNA activate an amyloidogenic process of physiological liquid-to-solid transition will provide alternative insights into pathological amyloidogenesis involved in many human diseases. Finally, our planned experiments on polyadenylated RNA storage by A-bodies will unveil new regulatory pathways in RNA biology. Our research program is of general interest to scientists studying nuclear/cytoplasmic structures, cellular response to stress, long noncoding RNA biology, and physiological/pathological amyloidogenesis.