Institute for Molecular Virology, University of Minnesota - Twin Cities, Minneapolis, MN 55455, USA; Comparative Molecular Biosciences Graduate Program, University of Minnesota - Twin Cities, St. Paul, MN 55108, USA.
Institute for Molecular Virology, University of Minnesota - Twin Cities, Minneapolis, MN 55455, USA; Division of Basic Sciences, School of Dentistry, University of Minnesota - Twin Cities, Minneapolis, MN 55455, USA; Masonic Cancer Center, University of Minnesota - Twin Cities, Minneapolis, MN 55455, USA.
J Mol Biol. 2022 Oct 15;434(19):167753. doi: 10.1016/j.jmb.2022.167753. Epub 2022 Jul 19.
Human immunodeficiency virus (HIV) Gag drives virus particle assembly. The capsid (CA) domain is critical for Gag multimerization mediated by protein-protein interactions. The Gag protein interaction network defines critical aspects of the retroviral lifecycle at steps such as particle assembly and maturation. Previous studies have demonstrated that the immature particle morphology of HIV-2 is intriguingly distinct relative to that of HIV-1. Based upon this observation, we sought to determine the amino acid residues important for virus assembly that might help explain the differences between HIV-1 and HIV-2. To do this, we conducted site-directed mutagenesis of targeted locations in the HIV-2 CA domain of Gag and analyzed various aspects of virus particle assembly. A panel of 31 site-directed mutants of residues that reside at the HIV-2 CA inter-hexamer interface, intra-hexamer interface and CA inter-domain linker were created and analyzed for their effects on the efficiency of particle production, particle morphology, particle infectivity, Gag subcellular distribution and in vitro protein assembly. Seven conserved residues between HIV-1 and HIV-2 (L19, A41, I152, K153, K157, N194, D196) and two non-conserved residues (G38, N127) were found to significantly impact Gag multimerization and particle assembly. Taken together, these observations complement structural analyses of immature HIV-2 particle morphology and Gag lattice organization as well as provide important comparative insights into the key amino acid residues that can help explain the observed differences between HIV immature particle morphology and its association with virus replication and particle infectivity.
人类免疫缺陷病毒 (HIV) Gag 驱动病毒颗粒组装。衣壳 (CA) 结构域对于通过蛋白-蛋白相互作用介导的 Gag 多聚化至关重要。Gag 蛋白相互作用网络定义了逆转录病毒生命周期的关键方面，例如颗粒组装和成熟。先前的研究表明，HIV-2 的不成熟颗粒形态与 HIV-1 明显不同。基于这一观察结果，我们试图确定对病毒组装重要的氨基酸残基，这可能有助于解释 HIV-1 和 HIV-2 之间的差异。为此，我们对 Gag 中的 HIV-2 CA 结构域的靶向位置进行了定点突变，并分析了病毒颗粒组装的各个方面。创建并分析了位于 HIV-2 CA 六聚体界面、六聚体内部界面和 CA 结构域连接子的 31 个定点突变体，以研究它们对颗粒产生效率、颗粒形态、颗粒感染性、Gag 亚细胞分布和体外蛋白组装的影响。在 HIV-1 和 HIV-2 之间保守的七个残基 (L19、A41、I152、K153、K157、N194、D196) 和两个非保守残基 (G38、N127) 被发现显著影响 Gag 多聚化和颗粒组装。总之，这些观察结果补充了不成熟 HIV-2 颗粒形态和 Gag 晶格组织的结构分析，并为关键氨基酸残基提供了重要的比较见解，这些残基有助于解释观察到的 HIV 不成熟颗粒形态与其与病毒复制和颗粒感染性的关联之间的差异。
