Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
Cell and Molecular Biology Graduate Group, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
mBio. 2020 Oct 27;11(5):e02623-20. doi: 10.1128/mBio.02623-20.
DEAD box RNA helicases regulate diverse facets of RNA biology. Proteins of this family carry out essential cellular functions, and emerging literature is revealing additional roles in immune defense. Using RNA interference screening, we identified an evolutionarily conserved antiviral role for the helicase DDX56 against the alphavirus Sindbis virus (SINV), a mosquito-transmitted pathogen that infects humans. Depletion of DDX56 enhanced infection in and human cells. Furthermore, we found that DDX56 also controls the emerging alphavirus chikungunya virus (CHIKV) through an interferon-independent mechanism. Using cross-linking immunoprecipitation (CLIP-Seq), we identified a predicted stem-loop on the viral genomic RNA bound by DDX56. Mechanistically, we found that DDX56 levels increase in the cytoplasm during CHIKV infection. In the cytoplasm, DDX56 impacts the earliest step in the viral replication cycle by binding and destabilizing the incoming viral genomic RNA, thereby attenuating infection. Thus, DDX56 is a conserved antiviral RNA binding protein that controls alphavirus infection. Arthropod-borne viruses are diverse pathogens and include the emerging virus chikungunya virus, which is associated with human disease. Through genetic screening, we found that the conserved RNA binding protein DDX56 is antiviral against chikungunya virus in insects and humans. DDX56 relocalizes from the nucleus to the cytoplasm, where it binds to a stem-loop in the viral genome and destabilizes incoming genomes. Thus, DDX56 is an evolutionarily conserved antiviral factor that controls alphavirus infection.
DEAD 框 RNA 解旋酶调节 RNA 生物学的多个方面。该家族的蛋白质执行重要的细胞功能，新兴文献揭示了它们在免疫防御中的额外作用。我们使用 RNA 干扰筛选，发现解旋酶 DDX56 对甲病毒辛德毕斯病毒（SINV）具有抗病毒作用，这是一种通过蚊子传播的病原体，可以感染人类。DDX56 的耗竭增强了 和人类细胞的感染。此外，我们发现 DDX56 通过干扰素非依赖性机制也控制新兴的甲病毒基孔肯雅病毒（CHIKV）。通过交联免疫沉淀（CLIP-Seq），我们鉴定出 DDX56 结合的病毒基因组 RNA 上的一个预测茎环结构。从机制上讲，我们发现 DDX56 在 CHIKV 感染期间在细胞质中增加。在细胞质中，DDX56 通过结合并破坏传入的病毒基因组 RNA 来影响病毒复制周期的最早步骤，从而减弱感染。因此，DDX56 是一种保守的抗病毒 RNA 结合蛋白，可控制甲病毒感染。节肢动物传播的病毒是多种多样的病原体，包括新兴的基孔肯雅病毒，它与人类疾病有关。通过遗传筛选，我们发现保守的 RNA 结合蛋白 DDX56 对昆虫和人类的基孔肯雅病毒具有抗病毒作用。DDX56 从细胞核重新定位到细胞质，在细胞质中它与病毒基因组中的茎环结合并使进入的基因组不稳定。因此，DDX56 是一种进化上保守的抗病毒因子，可控制甲病毒感染。
