Department of Microbiology, Mount Sinai School of Medicine, One Gustave L. Levy Place, New York, NY 10029, USA.
J Virol. 2010 May;84(10):5423-30. doi: 10.1128/JVI.02395-09. Epub 2010 Mar 10.
Interferon-stimulated expression and conjugation of the ubiquitin-like modifier ISG15 restricts replication of several viruses. Here, we established complete E1-activating, E2-conjugating, and E3 ligase-dependent expression systems for assaying both human and mouse ISGylation. We confirm that human HerC5, but not human HerC6, has ISG15 E3 ligase activity and identify mouse HerC6 as a bona fide ISG15 E3 ligase. Furthermore, we demonstrate that influenza B virus NS1 protein potently antagonizes human but not mouse ISGylation, a property dependent on B/NS1 binding the N-terminal domain of human but not mouse ISG15. Using chimeric human/mouse ISG15 constructs, we show that the B/NS1:ISG15 interaction is both necessary and sufficient to inhibit ISGylation regardless of the ligation machinery used. Inability to block ISGylation in certain species may contribute to limiting influenza B virus host range.
干扰素刺激的泛素样修饰物 ISG15 的表达和缀合限制了几种病毒的复制。在这里，我们建立了完整的 E1 激活、E2 缀合和 E3 连接酶依赖性表达系统，用于检测人和小鼠的 ISG 化。我们证实人 HerC5 而非人 HerC6 具有 ISG15 E3 连接酶活性，并鉴定出小鼠 HerC6 为真正的 ISG15 E3 连接酶。此外，我们证明乙型流感病毒 NS1 蛋白强烈拮抗人而非小鼠的 ISG 化，这一特性依赖于 B/NS1 与人而非小鼠 ISG15 的 N 端结构域结合。使用嵌合人/小鼠 ISG15 构建体，我们表明 B/NS1:ISG15 相互作用足以抑制 ISG 化，无论使用何种连接酶机制。在某些物种中无法阻止 ISG 化可能有助于限制乙型流感病毒的宿主范围。
