Department of Molecular Microbiology, School of Medicine, Washington University in St. Louis, St. Louis, Missouri, USA.
Department of Pathology & Immunology, School of Medicine, Washington University in St. Louis, St. Louis, Missouri, USA.
J Virol. 2023 Apr 27;97(4):e0006523. doi: 10.1128/jvi.00065-23. Epub 2023 Apr 5.
The establishment of the Orsay virus-Caenorhabditis elegans infection model has enabled the identification of host factors essential for virus infection. Argonautes are RNA interacting proteins evolutionary conserved in the three domains of life that are key components of small RNA pathways. C. elegans encodes 27 argonautes or argonaute-like proteins. Here, we determined that mutation of the argonaute-like gene 1, , results in a greater than 10,000-fold reduction in Orsay viral RNA levels, which could be rescued by ectopic expression of . Mutation in , a known interactor of ALG-1 and component of the RNA-induced silencing complex, also resulted in a significant reduction in Orsay virus levels. Viral RNA replication from an endogenous transgene replicon system was impaired by the lack of ALG-1, suggesting that ALG-1 plays a role during the replication stage of the virus life cycle. Orsay virus RNA levels were unaffected by mutations in the ALG-1 RNase H-like motif that ablate the slicer activity of ALG-1. These findings demonstrate a novel function of ALG-1 in promoting Orsay virus replication in C. elegans. All viruses are obligate intracellular parasites that recruit the cellular machinery of the host they infect to support their own proliferation. We used Caenorhabditis elegans and its only known infecting virus, Orsay virus, to identify host proteins relevant for virus infection. We determined that ALG-1, a protein previously known to be important in influencing worm life span and the expression levels of thousands of genes, is required for Orsay virus infection of C. elegans. This is a new function attributed to ALG-1 that was not recognized before. In humans, it has been shown that AGO2, a close relative protein to ALG-1, is essential for hepatitis C virus replication. This demonstrates that through evolution from worms to humans, some proteins have maintained similar functions, and consequently, this suggests that studying virus infection in a simple worm model has the potential to provide novel insights into strategies used by viruses to proliferate.
奥尔赛病毒-秀丽隐杆线虫感染模型的建立使得鉴定宿主感染病毒所必需的因子成为可能。Argonautes 是在生命的三个领域中进化保守的 RNA 相互作用蛋白，是小 RNA 途径的关键组成部分。秀丽隐杆线虫编码 27 种 Argonautes 或 Argonaute 样蛋白。在这里，我们确定 Argonaute 样基因 1（ALG-1）的突变导致奥尔赛病毒 RNA 水平降低超过 10000 倍，这可以通过外源性表达来挽救。已知与 ALG-1 相互作用并构成 RNA 诱导沉默复合物组成部分的基因ALG-2的突变也导致奥尔赛病毒水平显著降低。缺乏 ALG-1 会损害内源性转基因复制子系统中的病毒 RNA 复制，这表明 ALG-1 在病毒生命周期的复制阶段发挥作用。ALG-1 的 RNA 酶 H 样基序的突变不会影响奥尔赛病毒 RNA 水平，该基序使 ALG-1 的切割酶活性丧失。这些发现表明 ALG-1 在促进秀丽隐杆线虫中的奥尔赛病毒复制中具有新的功能。所有病毒都是专性细胞内寄生虫，它们利用宿主的细胞机制来支持自身的增殖。我们使用秀丽隐杆线虫及其唯一已知的感染病毒奥尔赛病毒，来鉴定与病毒感染相关的宿主蛋白。我们确定，以前已知对影响线虫寿命和数千个基因表达水平很重要的蛋白 ALG-1，是奥尔赛病毒感染秀丽隐杆线虫所必需的。这是以前未被认识到的 ALG-1 的新功能。在人类中，已经表明与 ALG-1 密切相关的蛋白 AGO2 是丙型肝炎病毒复制所必需的。这表明，从线虫到人类的进化过程中，一些蛋白质保持了相似的功能，因此，这表明在简单的线虫模型中研究病毒感染有可能为病毒增殖所采用的策略提供新的见解。
