Analysis of the Assembly Function of the Human Immunodeficiency Virus Type 1 Gag Protein Nucleocapsid Domain
Analysis of the Assembly Function of the Human Immunodeficiency Virus Type 1 Gag Protein Nucleocapsid Domain
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DOI：
10.1128/jvi.72.3.1782-1789.1998
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发表时间：
1998-03
影响因子：
5.4
通讯作者：
Yaqiang Zhang;Haoyu Qian;Z. Love;E. Barklis
中科院分区：
文献类型：
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作者：
Yaqiang Zhang;Haoyu Qian;Z. Love;E. Barklis
人类免疫缺陷病毒1型（HIV-1）核衣壳（NC）除了在RNA的特异性组装中发挥作用外，还参与了病毒颗粒的高效组装。然而，NC促进装配过程的机制尚未明确建立。形式上，NC可以通过将Pr 55 gag多聚蛋白限制为组装能力构象或通过掩蔽阻碍组装过程的残基来起作用。或者，NC结合RNA或进行蛋白质间接触的能力可能会影响颗粒组装。为了研究其在组装过程中的作用，我们用已知功能的多肽结构域替换了Pr 55 gag中的NC结构域，并分析了嵌合蛋白指导病毒样颗粒释放的能力。我们的研究结果表明，NC不掩盖抑制结构域，不被动地发挥作用，通过简单地提供一个稳定的折叠单体结构。然而，NC的多肽形成蛋白间接触的替代允许有效的病毒颗粒的组装和释放，即使在颗粒中没有检测到RNA。这些结果表明，NC形成的蛋白间接触是必不可少的正常HIV-1装配过程。
ABSTRACT Previous studies have shown that in addition to its function in specific RNA encapsidation, the human immunodeficiency virus type 1 (HIV-1) nucleocapsid (NC) is required for efficient virus particle assembly. However, the mechanism by which NC facilitates the assembly process is not clearly established. Formally, NC could act by constraining the Pr55 gag polyprotein into an assembly-competent conformation or by masking residues which block the assembly process. Alternatively, the capacity of NC to bind RNA or make interprotein contacts might affect particle assembly. To examine its role in the assembly process, we replaced the NC domain in Pr55 gag with polypeptide domains of known function, and the chimeric proteins were analyzed for their abilities to direct the release of virus-like particles. Our results indicate that NC does not mask inhibitory domains and does not act passively, by simply providing a stable folded monomeric structure. However, replacement of NC by polypeptides which form interprotein contacts permitted efficient virus particle assembly and release, even when RNA was not detected in the particles. These results suggest that formation of interprotein contacts by NC is essential to the normal HIV-1 assembly process.