Role of DNA sensors in host anti-retroviral defense

DNA传感器在宿主抗逆转录病毒防御中的作用

• 批准号: 9172791
• 负责人: SUSAN R ROSS
• 金额: $ 39.24万
• 依托单位: UNIVERSITY OF ILLINOIS AT CHICAGO
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-06-01 至 2021-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9172791
• 关键词: Address; Affect; Animals; Anti-Retroviral Agents; Betaretrovirus; Binding; Biochemical; Bioinformatics; Capsid; Cells; Coupled; Cyclic GMP; Cytoplasm; DNA; DNA Binding; Detection; Disease; Genes; Genetic Polymorphism; Human; Immune response; Infection; Infection Control; Interferons; Knock-out; Ligands; Molecular; Mouse Mammary Tumor Virus; Murine leukemia virus; Mus; Mutant Strains Mice; Nucleic Acids; Pathogenesis; Pathway interactions; Play; Post-Translational Protein Processing; Production; RNA; RNA Viruses; Retroviridae; Retroviridae Infections; Reverse Transcription; Role; Signal Transduction; Transcript; Transcriptase; Viral; Viral Load result; Virus; Virus Diseases; genetic approach; in vivo; knock-down; mutant; novel strategies; programs; receptor; response; sensor; viral DNA; viral RNA

Retroviruses are major causes of disease in animals and humans. Retroviruses replicate by reverse transcribing viral RNA into DNA, using the virus-encoded transcriptase. Since uncoating as well as reverse transcription occur in the cytoplasm, there is the potential for recognition of “foreign” viral RNA or DNA by host sensors. Recently, a number of host sensors, including cGAS, DDX41 and the ALR IFI16, have been implicated in the recognition of cytosolic DNA. Using a mutant murine leukemia virus (MLV) with an unstable capsid that induces a strong IFNβ response, we found that reverse transcripts induced this response and identified three sensors in mice required for recognition – IFI203, DDX41 and cGAS - that signal via the STING pathway leading to increased IFN Using APOBEC3 knockout and STING mutant mice and cells, we showed that the host retroviral restriction factor APOBEC3 limits the levels of reverse transcripts that trigger cytosolic sensing. Moreover, we found that the role of nucleic acid sensing in vivo is to increased expression of IFN- regulated restriction factors like APOBEC3 that in turn reduce viral load. While the identification of sensors involved in recognition is an important first step, there as of yet many unanswered questions. While we and others have shown that host sensing of retroviral nucleic acid is dependent on reverse transcription and therefore must include DNA detection, the involvement of at least 3 different factors in the response to infection could mean that RNA or RNA/DNA are also recognized. Additionally, while it is well-accepted that DNA binding cGAS activates production of cyclic GMP-AMP and that this ligand in turn activates STING, whether IFI203 and DDX41 operate in the same or parallel pathways to induce IFN is not known. Finally, the relative importance of the different host sensors in controlling viral infection in vivo has yet to be elucidated. To address these questions, we propose to carry out the following aims: I. What retroviral nucleic acids serve as ligands for cGAS, IFI203 and DDX41? II. What role does each of the sensors play in in vivo control of infection? III. What is the pathway of action of cGAS, IFI203 and DDX41 in the response to retroviral infection? Understanding the initial host response to infection by retroviruses is critical to our ability to determine how these viruses establish persistent infection as well the discovery of novel approaches to intervene in these infections. Using a combination of functional and genetic approaches, this proposal will delineate the molecular means by which retroviral nucleic acids are sensed by cells, as well as to determine the significance of this sensing in in vivo infection and pathogenesis.

逆转录病毒是动物和人类疾病的主要原因。逆转录病毒通过反向复制 使用病毒编码的转录酶将病毒RNA转录成DNA。由于未涂层以及反向 当转录发生在细胞质中时，存在宿主识别“外来”病毒RNA或DNA的可能性 传感器.最近，包括cGAS、DDX 41和ALR IFI 16在内的许多主机传感器已被 与胞质DNA的识别有关。使用突变的鼠白血病病毒（MLV）， 衣壳诱导强烈的IFNβ反应，我们发现逆转录诱导这种反应， 在小鼠中确定了识别所需的三种传感器-IFI 203，DDX 41和cGAS -通过STING发出信号 使用APOBEC 3敲除和STING突变小鼠和细胞，我们发现， 宿主逆转录病毒限制因子APOBEC 3限制了逆转录病毒的水平， 感应此外，我们发现核酸传感在体内的作用是增加IFN-γ的表达 调节限制因子如APOBEC 3，从而降低病毒载量。 虽然识别中涉及的传感器的识别是重要的第一步，但迄今为止， 没有答案的问题虽然我们和其他人已经表明，宿主对逆转录病毒核酸的感知是不稳定的， 依赖于逆转录，因此必须包括DNA检测，涉及至少3 对感染的反应中的不同因素可能意味着RNA或RNA/DNA也被识别。 此外，虽然公认DNA结合cGAS激活环GMP-AMP的产生， 这种配体反过来激活STING，无论IFI 203和DDX 41在相同或平行的途径中运作， 诱导的干扰素尚不清楚。最后，不同宿主感受器在控制病毒中的相对重要性 体内感染尚待阐明。 为了解决这些问题，我们建议实现以下目标： I.哪些逆转录病毒核酸可作为cGAS、IFI 203和DDX 41的配体？ 二.每个传感器在体内感染控制中起什么作用？ 三. cGAS、IFI 203和DDX 41在逆转录病毒感染应答中的作用途径是什么？ 了解宿主对逆转录病毒感染的最初反应对我们确定如何感染的能力至关重要。 这些病毒建立了持续性感染，并发现了新的方法来干预这些病毒， 感染.使用功能和遗传方法的组合，这项建议将描绘分子 逆转录病毒核酸被细胞感知的手段，以及确定这种意义 检测体内感染和发病机制。