TRIM5α Disrupts the Structure of Assembled HIV-1 Capsid Complexes In Vitro
TRIM5α Disrupts the Structure of Assembled HIV-1 Capsid Complexes In Vitro
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DOI：
10.1128/jvi.00210-10
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发表时间：
2010-07-01
影响因子：
5.4
通讯作者：
Aiken, Christopher
中科院分区：
文献类型：
--
作者：
Black, Lesa R.;Aiken, Christopher
宿主限制因子TRIM 5 α在哺乳动物细胞中提供针对逆转录病毒感染的内在防御。TRIM 5 α通过在进入后但在逆转录完成之前靶向病毒衣壳来阻断感染，但这种相互作用是否直接改变病毒衣壳的结构尚不清楚。先前的一项研究报道，恒河猴TRIM 5 α蛋白与通过体外重组HIV-1 CA-NC蛋白组装形成的圆柱形复合物稳定缔合，并且限制导致靶细胞中加速的HIV-1脱壳。为了进一步了解TRIM 5 α依赖性限制的机制，我们通过电子显微镜检查了TRIM 5蛋白对预组装的CA-NC复合物的结构影响。用表达限制性恒河猴TRIM 5 α蛋白的细胞裂解物孵育组装的复合物导致复合物的正常圆柱形结构的显著破坏。相反，与对照细胞或表达相当水平的非限制性人TRIM 5 α蛋白的细胞的裂解物一起孵育对复合物几乎没有影响。与表达TRIMCyp限制因子的细胞的裂解物一起孵育也破坏圆柱体。TRIMCyp的作用通过加入环孢霉素来阻止，环孢霉素抑制TRIMCyp与HIV-1衣壳的结合。因此，TRIM 5 α和TRIMCyp对CA-NC圆柱体的破坏与限制的特异性相关。总的来说，这些结果表明，HIV-1感染的TRIM 5 α依赖性限制是由病毒衣壳的结构扰动导致靶细胞中异常的HIV-1脱壳引起的。
The host restriction factor TRIM5 alpha provides intrinsic defense against retroviral infections in mammalian cells. TRIM5 alpha blocks infection by targeting the viral capsid after entry but prior to completion of reverse transcription, but whether this interaction directly alters the structure of the viral capsid is unknown. A previous study reported that rhesus macaque TRIM5 alpha protein stably associates with cylindrical complexes formed by assembly of recombinant HIV-1 CA-NC protein in vitro and that restriction leads to accelerated HIV-1 uncoating in target cells. To gain further insight into the mechanism of TRIM5 alpha-dependent restriction, we examined the structural effects of TRIM5 proteins on preassembled CA-NC complexes by electron microscopy. Incubation of assembled complexes with lysate of cells expressing the restrictive rhesus TRIM5 alpha protein resulted in marked disruption of the normal cylindrical structure of the complexes. In contrast, incubation with lysate of control cells or cells expressing comparable levels of the nonrestrictive human TRIM5 alpha protein had little effect on the complexes. Incubation with lysate of cells expressing the TRIMCyp restriction factor also disrupted the cylinders. The effect of TRIMCyp was prevented by the addition of cyclosporine, which inhibits binding of TRIMCyp to the HIV-1 capsid. Thus, disruption of CA-NC cylinders by TRIM5 alpha and TRIMCyp was correlated with the specificity of restriction. Collectively, these results suggest that TRIM5 alpha-dependent restriction of HIV-1 infection results from structural perturbation of the viral capsid leading to aberrant HIV-1 uncoating in target cells.