The Bioorganic Chemistry of RNA editing by ADARs

ADAR 编辑 RNA 的生物有机化学

• 批准号: 8143556
• 负责人: PETER A. BEAL
• 金额: $ 27.87万
• 依托单位: UNIVERSITY OF CALIFORNIA AT DAVIS
• 依托单位国家: 美国
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-03-01 至 2015-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8143556
• 关键词: ADAR1; Address; Adenosine; Aging; Amino Acids; Amyotrophic Lateral Sclerosis; Antisense Oligonucleotides; Behavior; Biochemistry; Biological Process; Chemistry; Codon Nucleotides; Complex; Coupled; Crystallization; Cyclic Peptides; DNA Repair; DNA Repair Enzymes; DRADA2b protein; Deaminase; Deamination; Enzymes; Epigenetic Process; Epilepsy; G-Protein-Coupled Receptors; Gated Ion Channel; Gene Expression; Genetic Techniques; Guanosine; Human; Inosine; Knowledge; Lead; Length; Ligands; Link; Malignant Neoplasms; Maps; Mental Depression; Messenger RNA; Methods; Modification; Molecular Biology Techniques; Nervous System Physiology; Nervous system structure; Peptoids; Prader-Willi Syndrome; Process; Proteins; RNA; RNA Binding; RNA Editing; Reaction; Regulation; Reporting; Research; Research Design; Role; Saccharomyces cerevisiae; Site; Structure; Structure-Activity Relationship; Synthesis Chemistry; Testing; Therapeutic; Time; Tissues; Transcript; Translations; Vertebral column; base; follow-up; genetic selection; human disease; inhibitor/antagonist; mRNA Precursor; mutant; novel; nucleoside analog; protein function; small molecule; tool; voltage

DESCRIPTION (provided by applicant): The RNA editing ADAR enzymes convert adenosines to inosines in RNA. Since inosine is decoded as guanosine during translation, this modification can lead to changes in the meaning of codons (recoding). There are at least 50 different A to I sites in human mRNAs that cause recoding. Recoding is common in the nervous system with targets including ligand-gated ion channels, voltage-gated ion channels and G-protein coupled receptors. Indeed, ADARs are necessary for a properly functioning nervous system and are known to regulate behavior in metazoans. However, little is known about the effect of recoding for targets with roles outside the nervous system. Perturbations in A to I editing have been observed in several human diseases including amyotrophic lateral sclerosis (ALS), dyschromatosis symmetrica hereditaria (DSH), Prader-Willi syndrome (PWS), epilepsy, depression and cancer. A recent study also implicates ADARs in the control of aging. Despite the significance of this form of epigenetics, our understanding of the mechanism and regulation of A to I editing is deficient. For instance, the selectivity for specific adenosines within ADAR substrates remains difficult to fully explain due to a lack of detailed characterization for ADAR-RNA complexes. Furthermore, pharmacological methods for controlling RNA editing do not currently exist limiting the types of studies possible to probe its biological function. In this competitive renewal of an R01 project, these knowledge gaps will be addressed through the application of synthetic chemistry coupled with techniques from molecular biology and biochemistry. The results of these studies will extend our basic understanding of the process of RNA editing and its effects on protein function as well as lead to new methods for its control. Methods for site-selective inhibition of RNA editing will be developed. Backbone modified antisense oligonucleotides and helix- threading peptoids that target RNA editing substrates will be investigated for this purpose. In addition, we will define factors controlling editing selectivity and mechanisms of inhibition for the ADAR2 reaction. A functional screen will be used to define the importance in controlling editing site selectivity of the length and sequence in a linker structure between two ADAR2-RNA interaction domains. In addition, ADAR2 mutants containing unnatural amino acids and RNA containing nucleoside analogs will be used to map ADAR2-RNA interactions. A novel genetic selection will identify cyclic peptide inhibitors of ADAR2 and follow-up studies with these inhibitors will identify points in the ADAR2 reaction susceptible to small molecule control. In addition, we will define the basis for ADAR1 editing of the mRNA for the DNA repair enzyme NEIL1. These efforts will define structure/activity relationships for the ADAR1 reaction and extend our understanding of the recoding of targets with functions outside the nervous system. Finally, this project will produce new molecules for crystallization trials of ADAR-RNA complexes. PUBLIC HEALTH RELEVANCE: RNA editing catalyzed by the ADAR enzymes is a form of epigenetic control of gene expression that is perturbed in a variety of human diseases including amyotrophic lateral sclerosis (ALS), dyschromatosis symmetrica hereditaria (DSH), Prader-Willi syndrome (PWS), epilepsy, depression and cancer. The proposed studies will extend our basic understanding of the process of RNA editing as well as lead to new methods for its control.

描述（由申请人提供）：RNA编辑ADAR酶将RNA中的腺苷转化为肌苷。由于肌苷在翻译过程中被解码为鸟苷，因此这种修饰可能导致密码子含义的变化（重新编码）。人类 mRNA 中至少有 50 个不同的 A 到 I 位点会导致重新编码。重新编码在神经系统中很常见，其靶标包括配体门控离子通道、电压门控离子通道和 G 蛋白偶联受体。事实上，ADAR 对于神经系统的正常运作是必需的，并且已知可以调节后生动物的行为。然而，对于神经系统之外的目标重新编码的影响知之甚少。 A 至 I 编辑的扰动已在多种人类疾病中观察到，包括肌萎缩侧索硬化症 (ALS)、遗传性对称性色素异常症 (DSH)、普瑞德威利综合征 (PWS)、癫痫、抑郁症和癌症。最近的一项研究还表明 ADAR 可以控制衰老。尽管这种形式的表观遗传学具有重要意义，但我们对 A 至 I 编辑的机制和调控的理解仍然不足。例如，由于缺乏 ADAR-RNA 复合物的详细表征，ADAR 底物内特定腺苷的选择性仍然难以完全解释。此外，目前不存在控制RNA编辑的药理学方法，限制了可能探测其生物学功能的研究类型。在 R01 项目的竞争性更新中，这些知识差距将通过应用合成化学以及分子生物学和生物化学技术来解决。这些研究的结果将扩展我们对 RNA 编辑过程及其对蛋白质功能影响的基本理解，并带来新的控制方法。将开发RNA编辑的位点选择性抑制方法。为此目的，将研究靶向RNA编辑底物的主链修饰的反义寡核苷酸和螺旋螺纹类肽。此外，我们将定义控制编辑选择性的因素和 ADAR2 反应的抑制机制。功能筛选将用于定义控制两个 ADAR2-RNA 相互作用域之间的接头结构中的长度和序列的编辑位点选择性的重要性。此外，含有非天然氨基酸的 ADAR2 突变体和含有核苷类似物的 RNA 将用于绘制 ADAR2-RNA 相互作用图谱。一种新的基因选择将鉴定 ADAR2 的环肽抑制剂，并且对这些抑制剂的后续研究将鉴定 ADAR2 反应中易受小分子控制的点。此外，我们还将定义 ADAR1 编辑 DNA 修复酶 NEIL1 mRNA 的基础。这些努力将定义 ADAR1 反应的结构/活性关系，并扩展我们对具有神经系统外功能的目标重新编码的理解。最后，该项目将生产用于 ADAR-RNA 复合物结晶试验的新分子。 公共健康相关性：ADAR 酶催化的 RNA 编辑是基因表达的表观遗传控制的一种形式，在多种人类疾病中受到干扰，包括肌萎缩侧索硬化症 (ALS)、遗传性对称性色素异常 (DSH)、普瑞德威利综合征 (PWS)、癫痫、抑郁症和癌症。拟议的研究将扩展我们对 RNA 编辑过程的基本理解，并带来新的控制方法。