Hepatitis C virus (HCV) remains a major human pathogen that requires better understanding of virus-host interactions. In this study, we performed a genome-wide CRISPR-Cas9 screening and identified TRIM26, an E3 ligase, as a critical HCV host factor. Deficiency of TRIM26 specifically impairs HCV genome replication. Mechanistic studies showed that TRIM26 interacts with HCV-encoded NS5B protein and mediates its K27-linked ubiquitination at residue K51, and thus promotes the NS5B-NS5A interaction. Moreover, mouse TRIM26 does not support HCV replication because of its unique six–amino acid insert that prevents its interaction with NS5B. Ectopic expression of human TRIM26 in a mouse hepatoma cell line that has been reconstituted with other essential HCV host factors promotes HCV infection. In conclusion, we identified TRIM26 as a host factor for HCV replication and a new determinant of host tropism. These results shed light on HCV-host interactions and may facilitate the development of an HCV animal model.

丙型肝炎病毒 (HCV) 仍然是一种主要的人类病原体，需要更好地了解病毒与宿主的相互作用。在这项研究中，我们进行了全基因组 CRISPR-Cas9 筛选，并将一种 E3 连接酶 TRIM26 鉴定为关键的 HCV 宿主因子。TRIM26 的缺乏会特异性地损害 HCV 基因组的复制。机理研究表明，TRIM26 与 HCV 编码的 NS5B 蛋白相互作用，并在残基 K51 处介导其 K27 连接的泛素化，从而促进 NS5B-NS5A 相互作用。此外，小鼠 TRIM26 不支持 HCV 复制，因为其独特的六氨基酸插入物阻止了其与 NS5B 的相互作用。人TRIM26在用其他必需HCV宿主因子重组的小鼠肝癌细胞系中的异位表达促进了HCV感染。综上所述，我们将TRIM26鉴定为HCV复制的宿主因子和宿主嗜性的新决定因素。这些结果揭示了 HCV 与宿主的相互作用，并可能促进 HCV 动物模型的开发。