Division of Infectious Disease, Department of Medicine, Vanderbilt University School of Medicine, AA-2205E Medical Center North, Nashville, TN 37232-2358, USA.
J Virol. 2011 Sep;85(18):9314-26. doi: 10.1128/JVI.00273-11. Epub 2011 Jul 13.
APOBEC3G (A3G) is packaged into human immunodeficiency virus type 1 (HIV-1) virions unless HIV-1 virion infectivity factor (Vif) counteracts it. Virion A3G restricts HIV-1 reverse transcription and integration in target cells. Some A3G in producer cells colocalizes with specific cytoplasmic structures, in what are called "A3G complexes" here. Functional effects of producer cell A3G complexes on HIV-1 replication were studied. HeLa cells were cotransfected with HIV-1 constructs producing pseudoviruses, as well as either wild-type (WT) A3G or a mutant A3G (C97A, Y124A, W127A, or D128K A3G). Pseudovirus particle production was decreased from cells expressing any of the A3Gs that formed complexes by 24 h after transfection, relative to cells with C97A A3G that did not form detectable A3G complexes by 24 h or A3G-negative cells. The intracellular HIV-1 Gag half-life was shorter in cells containing A3G complexes than in those lacking complexes. HIV-1 virion output was decreased in a single round of replication from a T cell line containing A3G complexes (CEM cells) after infection with Vif-negative HIV-1, compared to Vif-positive HIV-1 that depleted A3G. Levels of production of Vif-negative and Vif-positive virus were similar from cells not containing A3G (CEM-SS cells). Knockdown of the mRNA processing body (P-body) component RCK/p54, eliminated A3G complex formation, and increased HIV-1 production. We conclude that endogenous A3G complexes in producer cells decrease HIV-1 production if not degraded by Vif.
载脂蛋白 B mRNA 编辑酶催化多肽 3G（A3G）被包装到人类免疫缺陷病毒 1 型（HIV-1）病毒粒子中，除非 HIV-1 病毒粒子感染性因子（Vif）抵消了它的作用。病毒 A3G 限制 HIV-1 在靶细胞中的逆转录和整合。一些产生细胞中的 A3G 与特定的细胞质结构共定位，在这里称为“ A3G 复合物”。研究了产生细胞 A3G 复合物对 HIV-1 复制的功能影响。用 HIV-1 构建体共转染 HeLa 细胞，以产生假病毒，以及野生型（WT）A3G 或突变体 A3G（C97A、Y124A、W127A 或 D128K A3G）。与转染后 24 小时未形成可检测 A3G 复合物的 C97A A3G 细胞或 A3G 阴性细胞相比，表达任何形成复合物的 A3G 的细胞中假病毒粒子的产生在转染后 24 小时降低。含有 A3G 复合物的细胞中细胞内 HIV-1 Gag 半衰期比缺乏复合物的细胞短。与耗竭 A3G 的 Vif 阳性 HIV-1 相比，感染 Vif 阴性 HIV-1 后，含有 A3G 复合物的 T 细胞系（CEM 细胞）中的 HIV-1 病毒粒子输出量在一轮复制中减少。来自不含有 A3G（CEM-SS 细胞）的细胞的 Vif 阴性和 Vif 阳性病毒的产量相似。mRNA 加工体（P 体）成分 RCK/p54 的敲低消除了 A3G 复合物的形成，并增加了 HIV-1 的产生。我们得出结论，如果 A3G 复合物不被 Vif 降解，那么产生细胞中的内源性 A3G 复合物会降低 HIV-1 的产生。
