Hepatitis A virus (HAV) is a positive-sense RNA virus causing acute inflammation of the liver. Here, using a genome-scale CRISPR screen in a human hepatocyte cell line, we provide a comprehensive picture of the cellular factors, which are exploited by HAV during replication. We identified genes involved in sialic acid biosynthesis and members of the eukaryotic translation initiation factor complex, corroborating their putative roles in HAV infection. Additionally, we uncovered all components of the cellular machinery for UFMylation, a ubiquitin-like protein modification. We showed that HAV translation specifically depends on UFM1 conjugation of the ribosomal protein RPL26. Furthermore, we found that components related to the yeast Trf4/5-Air1/2-Mtr4 polyadenylation (TRAMP) complex, are required for viral translation, independent of controlling HAV poly(A) tails. While the identified HAV host factors were largely distinct compared to other picornaviruses, we highlighted a surprising co-dependency of HAV and hepatitis B virus (HBV) on the TRAMP-like complex. Finally, we demonstrated that pharmacological inhibition of the TRAMP-like complex decreased HAV replication in hepatocyte cells and human liver organoids, thus providing a strategy for host-directed therapy of HAV infection.

中文翻译：

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全基因组CRISPR筛选将UFMylation和TRAMP样复合物鉴定为甲型肝炎病毒感染所需的宿主因子

甲型肝炎病毒（HAV）是导致肝脏急性炎症的正向RNA病毒。在这里，在人类肝细胞系中使用基因组规模的CRISPR筛选，我们提供了细胞因子的全面图片，这些因子在复制过程中被HAV利用。我们确定了与唾液酸生物合成有关的基因和真核翻译起始因子复合物的成员，从而证实了它们在HAV感染中的假定作用。此外，我们发现了UFMylation（一种遍在蛋白样蛋白修饰）细胞机制的所有组成部分。我们表明，HAV翻译特别取决于核糖体蛋白RPL26的UFM1偶联。此外，我们发现病毒翻译需要与酵母Trf4 / 5-Air1 / 2-Mtr4聚腺苷酸化（TRAMP）复合体相关的成分，独立于控制HAV poly（A）尾巴。尽管与其他小核糖核酸病毒相比，已鉴定出的HAV宿主因素大不相同，但我们强调了HAV和乙型肝炎病毒（HBV）对TRAMP样复合物的惊人依赖性。最后，我们证明了TRAMP样复合物的药理抑制作用会降低肝细胞和人肝类器官中的HAV复制，从而为针对宿主的HAV感染治疗提供了一种策略。