Mechanism of the Antiviral Activity of BAF Against Poxvirus and HSV-1 Infection

BAF 对抗痘病毒和 HSV-1 感染的抗病毒活性机制

• 批准号: 9413298
• 负责人: MATTHEW S WIEBE
• 金额: $ 36.83万
• 依托单位: UNIVERSITY OF NEBRASKA LINCOLN
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-02-01 至 2020-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9413298
• 关键词: Address; Adenoviruses; Antiviral Agents; Antiviral Response; Binding; Binding Proteins; Biochemical; Cell Nucleus; Cell physiology; Cells; Communicable Diseases; Complex; Cytoplasm; DNA; DNA Binding; DNA Damage; DNA Repair; DNA Viruses; DNA biosynthesis; DNA-Binding Proteins; DNA-Protein Interaction; Data; Defense Mechanisms; Development; Diagnostic; Ensure; Enzymes; Euchromatin; Future; Genetic; Genetic Transcription; Genome; Goals; Growth; HIV; Herpesviridae; Herpesvirus 1; Host Defense; Host Defense Mechanism; Immune; Impairment; Infection; Investigation; Knowledge; Laboratory Study; Link; Maintenance; Mediating; Mitosis; Mitotic; Modeling; Molecular; Nuclear; Nucleoproteins; Outcome; Pathway interactions; Phosphorylation; Phosphotransferases; Post-Translational Regulation; Poxviridae; Process; Property; Proteins; Regulation; Repression; Research; Role; Signal Pathway; Signal Transduction; Testing; Transcriptional Regulation; Vaccinia; Viral; Viral Physiology; Virus; Virus Diseases; Virus Replication; Work; barrier-to-autointegration factor; base; cell growth regulation; ds-DNA; extrachromosomal DNA; genome integrity; inhibitor/antagonist; innovation; insight; pathogen; protein complex; public health relevance; recruit; response; scaffold; sensor; targeted treatment; tool; transcription factor; viral DNA

 DESCRIPTION (provided by applicant): Much remains to be learned about mechanisms cells utilize to defend against foreign DNA, both in the cytoplasm and nucleus, as well as how these defenses are subverted by viral countermeasures during infection. To address this knowledge gap, our studies of host defenses against foreign DNA focus on the poxvirus vaccinia and HSV1 as model pathogens. Understanding how these viruses accomplish DNA replication and transcription will yield new insights into the defense mechanisms cells use to respond to all foreign DNA. Toward this goal, our studies of vaccinia have led to the discovery that the poxviral B1 kinase is essential for viral DNA replication because it is needed to inactivate the cellular DNA binding protein BAF (barrier to autointegration factor). If it is not inactivated, BAF binds to viral DNA and acts as a defense against vaccinia DNA replication. Recent data from our lab suggests that BAF can act as an HSV1 inhibitor as well, indicating BAF may impair growth of multiple DNA viruses. BAF's antiviral activity likely occurs via its ability to compact and aggregate DNA to which it binds; we postulate that this compaction may contribute to host defense in multiple ways. For example, compaction likely limits the accessibility of the DNA to viral replication proteins via steric hindrance, and facilitates binding of other antiviral protein to the foreign genomes. Further examination of BAF's antiviral activity will yield unique insights int its mechanism of action. Our central hypothesis is that BAF initiates the assembly of DNA:protein complexes in a phosphorylation-regulated manner, providing a scaffold on which intrinsic defense effectors can converge. To test our hypothesis we propose three aims. AIM 1) Determine how phosphorylation and localization both regulate BAF's repression of poxviral DNA replication. These studies will yield insights into how post-translational regulation and localization provide interconnected mechanisms of regulating BAF's host defense activity. AIM 2) Determine how BAF- DNA complexes modulate transcription and DDR signaling to protect genomic integrity. Understanding how BAF and DNA repair machinery coordinate the silencing of foreign DNA, but are eluded by poxviruses, will be a central focus of this aim. AIM 3) Determine the mechanism whereby BAF acts as an antiviral against HSV-1 infection. Our data demonstrate that BAF can impair HSV-1 infection in a manner regulated by localization and/or phosphorylation, thus paralleling how BAF's anti-poxviral activity is modulated. These studies will yield insights into the molecular mechanism of BAF's activity against HSV-1. Throughout the course of these studies, we will compare and contrast how BAF works against both a cytoplasmic and a nuclear DNA virus, which will be an innovative application of these pathogens. As an outcome of this work we will better understand BAF's contribution to these nucleoprotein complexes and how BAF itself is regulated during viral infection. Thus, we will gain insight into cellular mechanisms which overlap in their ability to 1) silence foreign DNA through compaction and 2) protect genome integrity even in the absence of infection.

 描述(由申请人提供)：关于细胞在细胞质和细胞核中用来防御外来DNA的机制，以及在感染过程中病毒对策如何颠覆这些防御机制，仍有许多有待了解。为了解决这一认识差距，我们对宿主对外来DNA的防御研究集中在痘病毒、牛痘和HSV1作为模式病原体。了解这些病毒是如何完成DNA复制和转录的，将为细胞用来应对所有外来DNA的防御机制提供新的见解。为了实现这一目标，我们对痘苗病毒的研究发现，痘病毒B1激酶是病毒DNA复制所必需的，因为它是灭活细胞DNA结合蛋白BAF(自整合因子屏障)所必需的。如果未停用，则BAF绑定到 病毒DNA，并起到防御牛痘DNA复制的作用。我们实验室最近的数据表明，BAF也可以作为HSV1的抑制剂，这表明BAF可能会损害多种DNA病毒的生长。BaF的抗病毒活性可能是通过其紧凑和聚集其结合的DNA的能力而发生的；我们假设这种紧凑可能以多种方式有助于宿主防御。例如，压缩作用可能通过空间位阻限制DNA与病毒复制蛋白的可及性，并促进其他抗病毒蛋白与外源基因组的结合。进一步研究BAF的抗病毒活性将对其作用机制产生独特的见解。我们的中心假设是，BAF以一种磷酸化调节的方式启动DNA：蛋白质复合体的组装，为内在防御效应器提供一个聚合的支架。为了检验我们的假设，我们提出了三个目标。目的1)确定磷酸化和定位对BAF抑制痘病毒DNA复制的调节作用。这些研究将深入了解翻译后调节和本地化如何提供相互关联的机制来调节BAF的宿主防御活动。目的2)确定BAF-DNA复合体如何调节转录和DDR信号以保护基因组的完整性。了解BAF和DNA修复机制如何协调外来DNA的沉默，但却被痘病毒避开，将是这一目标的中心焦点。目的3)探讨BAF抗HSV-1感染的作用机制。我们的数据表明，BAF可以通过定位和/或磷酸化调节的方式削弱HSV-1感染，从而平行于BAF的抗痘病毒活性的调节。这些研究将对BAF抗HSV-1的分子机制有更深入的了解。在整个研究过程中，我们将比较和对比BAF对细胞质和核DNA病毒的作用方式，这将是这些病原体的创新应用。作为这项工作的结果，我们将更好地了解BAF对这些核蛋白复合体的贡献，以及BAF本身在病毒感染过程中是如何受到调节的。因此，我们将深入了解细胞机制，这些机制在1)通过紧凑使外来DNA沉默和2)即使在没有感染的情况下也保护基因组完整性的能力上存在重叠。