Department of Biological Sciences, University of Toledo, 2801 West Bancroft Street, Toledo, OH 43606, USA.
College of Sciences, Auburn University at Montgomery, 7400 East Dr., Montgomery, AL 36117, USA.
Viruses. 2023 Feb 7;15(2):466. doi: 10.3390/v15020466.
Virus infection activates integrated stress response (ISR) and stress granule (SG) formation and viruses counteract by interfering with SG assembly, suggesting an important role in antiviral defense. The infection of fish cells by Viral Hemorrhagic Septicemia Virus (VHSV), activates the innate immune recognition pathway and the production of type I interferon (IFN). However, the mechanisms by which VHSV interacts with ISR pathway regulating SG formation is poorly understood. Here, we demonstrate that fish cells respond to heat shock, oxidative stress and VHSV infection by forming SG that localized key SG marker, Ras GTPase-activating protein (SH3 domain)-binding protein 1 (G3BP1). We show that PKR-like endoplasmic reticulum kinase (PERK), but not (dsRNA)-dependent protein kinase (PKR), is required for VHSV-induced SG formation. Furthermore, in VHSV Ia infected cells, PERK activity is required for IFN production, antiviral signaling and viral replication. SG formation required active virus replication as individual VHSV Ia proteins or inactive virus did not induce SG. Cells lacking G3BP1 produced increased IFN, antiviral genes and viral mRNA, however viral protein synthesis and viral titers were reduced. We show a critical role of the activation of ISR pathway and SG formation highlighting a novel role of G3BP1 in regulating VHSV protein translation and replication.
病毒感染会激活整合应激反应（ISR）和应激颗粒（SG）的形成，病毒会通过干扰 SG 组装来对抗，这表明其在抗病毒防御中起着重要作用。鱼类细胞感染病毒性出血性败血症病毒（VHSV）会激活先天免疫识别途径和 I 型干扰素（IFN）的产生。然而，VHSV 与 ISR 途径相互作用调节 SG 形成的机制还知之甚少。在这里，我们证明鱼类细胞通过形成 SG 来应对热休克、氧化应激和 VHSV 感染，SG 定位于关键的 SG 标记物 Ras GTPase-activating protein (SH3 domain)-binding protein 1 (G3BP1)。我们表明 PKR 样内质网激酶（PERK），而不是双链 RNA 依赖性蛋白激酶（PKR），是 VHSV 诱导 SG 形成所必需的。此外，在 VHSV Ia 感染的细胞中，PERK 活性对于 IFN 的产生、抗病毒信号和病毒复制是必需的。SG 的形成需要活跃的病毒复制，因为单个 VHSV Ia 蛋白或失活的病毒不会诱导 SG。缺乏 G3BP1 的细胞产生更多的 IFN、抗病毒基因和病毒 mRNA，但病毒蛋白合成和病毒滴度降低。我们证明了 ISR 途径和 SG 形成的激活起着关键作用，突出了 G3BP1 在调节 VHSV 蛋白翻译和复制中的新作用。
