Functional analysis of downstream open chromatin induced in HSV-1 infection

HSV-1 感染诱导的下游开放染色质的功能分析

• 批准号: 412048193
• 负责人: Professor Dr. Lars Dölken
• 金额: --
• 依托单位: Institut für Virologie und Immunbiologie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2018
• 资助国家: 德国
• 起止时间: 2017-12-31 至 2021-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/412048193?language=en
• 关键词: Functional; analysis; downstream; open; chromatin

Herpes simplex virus 1 (HSV-1) is the causative agent of the common cold sores but also responsible for severe life-threatening diseases including encephalitis, pneumonia, hepatitis and generalized skin infections. Furthermore, HSV-1 is a paradigm for virus-induced host shut-off exerted at RNA level. Recently, we showed that HSV-1 triggers a widespread disruption of transcription termination (DoTT) of cellular but not viral genes, resulting in extensive read-through transcription beyond poly(A) sites. Subsequently, similar observations were also reported in cellular stress responses and cancer. We now found that HSV-1 induced DoTT resembles a cellular stress response and leads to nuclear retention of read-through transcripts, thereby contributing to host shut-off. The focus of the current application is the striking observation that HSV-1-induced DoTT, but not stress-induced read-through transcription, was accompanied by an extensive increase in chromatin accessibility downstream of the affected poly(A) sites. These downstream open chromatin regions (dOCRs) extend for tens-of-thousands of nucleotides and essentially match the region of transcription read-through. In this proposal, we now seek to identify the molecular mechanism responsible for the induction of dOCRs and assess its functional relevance for productive HSV-1 infection. The proposed project combines wet-lab work and bioinformatics analyses to test our hypothesis that: (i) dOCRs in HSV-1 infection arise from an impairment in histone repositioning upon Pol II transcription into genomic regions outside of genes; (ii) histone release during dOCR formation explains the previously reported increase in the pool of free nucleoplasmic histones; (iii) the associated increase in histone mobility facilitates chromatinization of the replicating viral DNA. Results obtained from this work will detail how an important human pathogen manipulates the transcriptional machinery to promote productive viral replication. In addition, it will pioneer a fascinating new model for studying the molecular mechanisms orchestrating gene expression and chromatin architecture in human cells.

单纯疱疹病毒1（HSV-1）是常见感冒疮的病原体，但也是导致严重危及生命的疾病的原因，包括脑炎、肺炎、肝炎和全身皮肤感染。此外，HSV-1是在RNA水平上发挥病毒诱导的宿主关闭作用的范例。最近，我们发现HSV-1触发了细胞基因而不是病毒基因的广泛转录终止（DoTT）中断，导致广泛的通读转录超出poly（A）位点。随后，在细胞应激反应和癌症中也报道了类似的观察结果。我们现在发现HSV-1诱导的DoTT类似于细胞应激反应，并导致通读转录物的核保留，从而有助于宿主关闭。本申请的焦点是令人惊讶的观察结果，即HSV-1诱导的DoTT，而不是应激诱导的通读转录，伴随着受影响的poly（A）位点下游的染色质可及性的广泛增加。这些下游开放染色质区域（dOCR）延伸数万个核苷酸，并且基本上匹配转录通读区域。在这项提议中，我们现在试图确定负责诱导dOCR的分子机制，并评估其与生产性HSV-1感染的功能相关性。该项目结合了湿实验室工作和生物信息学分析，以验证我们的假设：（i）HSV-1感染中的dOCR是由Pol II转录到基因外的基因组区域时组蛋白重新定位的损伤引起的;（ii）dOCR形成过程中组蛋白的释放解释了先前报道的游离核质组蛋白库的增加;（iii）组蛋白迁移率的相关增加促进复制病毒DNA的染色质化。从这项工作中获得的结果将详细说明一个重要的人类病原体如何操纵转录机制，以促进生产性病毒复制。此外，它将开创一个迷人的新模型，用于研究人类细胞中基因表达和染色质结构的分子机制。