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A-Z junction formation drives recognition of Alu RNAs by ADAR1 and supports viral infectivity and replication

A-Z 连接的形成驱动 ADAR1 对 Alu RNA 的识别，并支持病毒的感染性和复制

基本信息

批准号：
10385045
负责人：
Parker J Nichols
金额：
$ 3.53万
依托单位：
UNIVERSITY OF COLORADO DENVER
依托单位国家：
美国
项目类别：
财政年份：
2021
资助国家：
美国
起止时间：
2021-12-01 至 2024-11-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10385045
关键词：
Adenosine Adopted Alu Elements Amplifiers Binding Binding Sites Biochemical Biological Process Biophysics Cells Characteristics DNA Deaminase Disease Double-Stranded RNA Binding Domain Event Foundations Genetic Transcription Growth Helix-Turn-Helix Motifs Human Human Genome Immune response Infection Inflammatory Response Innate Immune Response Innate Immune System Inosine Interferons Kinetics Knowledge Methods Molecular Molecular Conformation Mutation N-terminal NMR Spectroscopy Nature Pathway interactions Play Population Primates Proliferating Protein Isoforms Proteins RNA RNA Binding RNA Conformation RNA Editing RNA Recognition Motif Research Resolution Retrotransposon Role Sequencing Biochemistry Side Signal Transduction Specificity Structure TLR3 gene Techniques Testing Tissue-Specific Gene Expression Viral Virus Virus Diseases West Nile virus Work X-Ray Crystallography Z-Form DNA alpha helix biological adaptation to stress biological research conformational conversion cost design dsRNA adenosine deaminase experimental study fighting in vivo mutant prevent response structural biology synergism tool transcriptome transcriptome sequencing treatment strategy

项目摘要

Project Summary Self and non-self RNA must be distinguished by the cell in order to avoid triggering the innate immune response when not needed. In humans, self RNAs are edited by adenosine deaminase that acts on RNA (ADAR1), which modifies adenosines to inosines. The vast majority of A-to-I editing events occur in primate- specific Alu elements, which are the most prolific retrotransposon found within the human genome. Alu elements have been shown to be the primary drivers of RIG-I, MDA-5, and TLR3 signaling suggesting that the primary function of ADAR1-dependent editing of Alu elements is to suppress the immune response. Editing is augmented upon infection by viruses primarily through the activity of the longer, interferon-induced, isoform of ADAR1 (ADAR1p150), which is unique from the short isoform in that it has a N-terminal Z-RNA binding domain (Zα) and that it is pro-viral. This suggests that the Z-RNA binding function of Zα plays a critical role in targeting ADAR1p150 to Z-RNA-forming regions within Alu elements along with a nearby structurally homologous Zβ domain, however, the RNA binding mechanisms and specificities of ADAR1p150 are poorly characterized. My hypothesis is that the N-terminal Zα domain and the closely related Zβ domain augment A-to-I editing by targeting ADAR1p150 to Z-RNA-forming regions within Alu elements during the interferon response. This increased editing in-turn “blunts” the interferon response and allows many types of viruses to proliferate unchallenged. In this proposal, I present a strategy which integrates structural biology, RNA-sequencing, and biochemistry techniques to uncover specific Z-RNA-forming sequences within Alu elements and during infection and answer basic questions about A-to-Z RNA transitions in Alu elements by the Zα and Zβ domains of ADAR1p150. My specific aims are (Aim 1) to characterize the transition from A- to Z-RNA in Alu RNAs through biochemical and structural techniques. I also plan (Aim 2) to investigate how the Z-RNA recognizing ability of Zα and Zβ contributes to recognition and editing of Alu elements in vivo and how it correlates to West Nile infection of HEK293T cells by RNA-sequencing techniques. Due to our lack of knowledge about the Z- DNA/RNA binding domain of ADAR1, we have likely vastly overlooked the repertoire of RNA segments able to adopt Z-conformations within the transcriptome. The results of my proposal will help to fill this gap in knowledge, laying the foundations for further research on the importance of Z-RNA in biological processes and help guide studies attempting to manipulate A-to-I editing as a tool for treating many types of diseases or inhibit the pro-viral characteristics of ADAR1p150.

项目总结