Department of Translational Physiology, Infectiology and Public Health, Faculty of Veterinary Medicine, Ghent Universitygrid.5342.0, Ghent, Belgium.
McArdle Laboratory for Cancer Research, Department of Oncology, University of Wisconsin-Madison, Madison, Wisconsin, USA.
J Virol. 2022 Jul 13;96(13):e0071422. doi: 10.1128/jvi.00714-22. Epub 2022 Jun 22.
Pseudorabies virus (PRV) is a porcine alphaherpesvirus that belongs to the family. We showed earlier that infection of porcine epithelial cells with PRV triggers activation of the nuclear factor κB (NF-κB) pathway, a pivotal signaling axis in the early immune response. However, PRV-induced NF-κB activation does not lead to NF-κB-dependent gene expression. Here, using electrophoretic mobility shift assays (EMSAs), we show that PRV does not disrupt the ability of NF-κB to interact with its κB target sites. Assessing basal cellular transcriptional activity in PRV-infected cells by quantitation of prespliced transcripts of constitutively expressed genes uncovered a broad suppression of cellular transcription by PRV, which also affects the inducible expression of NF-κB target genes. Host cell transcription inhibition was rescued when viral genome replication was blocked using phosphonoacetic acid (PAA). Remarkably, we found that host gene expression shutoff in PRV-infected cells correlated with a substantial retention of the NF-κB subunit p65, the TATA box binding protein, and RNA polymerase II-essential factors required for (NF-κB-dependent) gene transcription-in expanding PRV replication centers in the nucleus and thereby away from the host chromatin. This study reveals a potent mechanism used by the alphaherpesvirus PRV to steer the protein production capacity of infected cells to viral proteins by preventing expression of host genes, including inducible genes involved in mounting antiviral responses. Herpesviruses are highly successful pathogens that cause lifelong persistent infections of their host. Modulation of the intracellular environment of infected cells is imperative for the success of virus infections. We reported earlier that a DNA damage response in epithelial cells infected with the alphaherpesvirus pseudorabies virus (PRV) results in activation of the hallmark proinflammatory NF-κB signaling axis but, remarkably, that this activation does not lead to NF-κB-induced (proinflammatory) gene expression. Here, we report that PRV-mediated inhibition of host gene expression stretches beyond NF-κB-dependent gene expression and in fact reflects a broad inhibition of host gene transcription, which correlates with a substantial recruitment of essential host transcription factors in viral replication compartments in the nucleus, away from the host chromatin. These data uncover a potent alphaherpesvirus mechanism to interfere with production of host proteins, including proteins involved in antiviral responses.
伪狂犬病病毒 (PRV) 是一种猪α疱疹病毒，属于疱疹病毒科。我们之前曾表明，PRV 感染猪上皮细胞会触发核因子 κB (NF-κB) 途径的激活，这是早期免疫反应中的关键信号轴。然而，PRV 诱导的 NF-κB 激活并不会导致 NF-κB 依赖性基因表达。在这里，我们使用电泳迁移率变动分析 (EMSA) 表明，PRV 不会破坏 NF-κB 与 κB 靶位点相互作用的能力。通过定量分析组成型表达基因的前拼接转录本来评估 PRV 感染细胞中的基础细胞转录活性，发现 PRV 广泛抑制了细胞转录，这也影响了 NF-κB 靶基因的诱导表达。当使用膦甲酸钠 (PAA) 阻断病毒基因组复制时，宿主细胞转录抑制得到挽救。值得注意的是，我们发现 PRV 感染细胞中的宿主基因表达关闭与 NF-κB 亚基 p65、TATA 框结合蛋白和 RNA 聚合酶 II 的大量保留相关，这些都是 (NF-κB 依赖性) 基因转录所必需的基本因子，这使得病毒复制中心在核内扩张，远离宿主染色质。这项研究揭示了 α疱疹病毒 PRV 通过阻止宿主基因的表达，包括参与抗病毒反应的诱导基因的表达，来引导感染细胞的蛋白质产生能力转向病毒蛋白的一种有效机制。疱疹病毒是一种非常成功的病原体，会导致其宿主的终身持续性感染。调节感染细胞的细胞内环境对于病毒感染的成功至关重要。我们之前曾报道，上皮细胞感染α疱疹病毒伪狂犬病病毒 (PRV) 会导致标志性的促炎 NF-κB 信号轴激活，但令人惊讶的是，这种激活不会导致 NF-κB 诱导的 (促炎) 基因表达。在这里，我们报告 PRV 介导的宿主基因表达抑制不仅超出了 NF-κB 依赖性基因表达的范围，实际上反映了宿主基因转录的广泛抑制，这与细胞核内病毒复制区大量募集必需的宿主转录因子相关，远离宿主染色质。这些数据揭示了一种有效的α疱疹病毒机制，可以干扰宿主蛋白的产生，包括参与抗病毒反应的蛋白。
