The C-Terminal α-Helix Domain of Apolipoprotein E Is Required for Interaction with Nonstructural Protein 5A and Assembly of Hepatitis C Virus
The C-Terminal α-Helix Domain of Apolipoprotein E Is Required for Interaction with Nonstructural Protein 5A and Assembly of Hepatitis C Virus
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DOI：
10.1128/jvi.01021-10
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发表时间：
2010-11-01
影响因子：
5.4
通讯作者：
Luo, Guangxiang
中科院分区：
文献类型：
--
作者：
Cun, Wei;Jiang, Jieyun;Luo, Guangxiang
我们最近已经证明，人载脂蛋白E（apoE）是丙型肝炎病毒（HCV）感染和组装所必需的（K.S. Chang，J. Jiang，Z. Cai和G. Luo，J. Virol. 81：13783-13793，2007; J. Jiang和G. Luo，J. Virol. 83：12680-12691，2009）。在本研究中，我们已经确定了载脂蛋白E在丙型肝炎病毒装配的重要性的分子基础。来自哺乳动物的双杂交研究的结果表明，apoE和HCV非结构蛋白5A（NS 5A）之间的特异性相互作用。apoE的C-末端三分之一本身足以与NS 5A相互作用。进行性缺失突变分析表明apoE的C-末端α-螺旋结构域对NS 5A结合很重要。apoE的N端受体结合域和C端20个氨基酸是apoE与NS 5A相互作用的关键。apoE的NS 5A结合结构域定位于氨基酸205和280之间的C-末端α-螺旋结构域的中间。同样，破坏apoE-NS 5A相互作用的缺失突变导致HCV产生的阻断。这些发现表明，特定的apoE-NS 5A相互作用是感染性HCV组装所必需的。此外，我们已经确定，使用apoE的不同主要亚型（E2，E3和E4）在apoE-NS 5A相互作用中没有显着差异。同样地，apoE的这三种主要同种型与感染性HCV的感染性和组装同样相容，表明apoE同种型在细胞培养物中不差异调节HCV的感染性和/或组装。
We have recently demonstrated that human apolipoprotein E (apoE) is required for the infectivity and assembly of hepatitis C virus (HCV) (K.S. Chang, J. Jiang, Z. Cai, and G. Luo, J. Virol. 81:13783-13793, 2007; J. Jiang and G. Luo, J. Virol. 83:12680-12691, 2009). In the present study, we have determined the molecular basis underlying the importance of apoE in HCV assembly. Results derived from mammalian two-hybrid studies demonstrate a specific interaction between apoE and HCV nonstructural protein 5A (NS5A). The C-terminal third of apoE per se is sufficient for interaction with NS5A. Progressive deletion mutagenesis analysis identified that the C-terminal alpha-helix domain of apoE is important for NS5A binding. The N-terminal receptor-binding domain and the C-terminal 20 amino acids of apoE are dispensable for the apoE-NS5A interaction. The NS5A-binding domain of apoE was mapped to the middle of the C-terminal alpha-helix domain between amino acids 205 and 280. Likewise, deletion mutations disrupting the apoE-NS5A interaction resulted in blockade of HCV production. These findings demonstrate that the specific apoE-NS5A interaction is required for assembly of infectious HCV. Additionally, we have determined that using different major isoforms of apoE (E2, E3, and E4) made no significant difference in the apoE-NS5A interaction. Likewise, these three major isoforms of apoE are equally compatible with infectivity and assembly of infectious HCV, suggesting that apoE isoforms do not differentially modulate the infectivity and/or assembly of HCV in cell culture.