The membrane-proximal tyrosine-based sorting signal of human immunodeficiency virus type 1 gp41 is required for optimal viral infectivity
The membrane-proximal tyrosine-based sorting signal of human immunodeficiency virus type 1 gp41 is required for optimal viral infectivity
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DOI：
10.1128/jvi.78.3.1069-1079.2004
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发表时间：
2004-02-01
影响因子：
5.4
通讯作者：
Guatelli, JC
中科院分区：
文献类型：
--
作者：
Day, JR;Münk, C;Guatelli, JC
人免疫缺陷病毒1型Env糖蛋白的胞质结构域中的基于膜近端酪氨酸的分选基序对于质膜的内吞作用、极化上皮细胞中病毒出芽的基底外侧靶向作用以及淋巴细胞质膜局部区域的极化出芽是重要的。为了研究Env分选基序（Y 712 XXL）在感染性、Env掺入病毒体和病毒进入中的作用，我们用酪氨酸至丙氨酸取代来破坏该基序。为了研究Env分选基序与Net增强感染性之间的关系，在Nef阳性和Nef阴性背景中进行EnvY 712 A置换。在扩散感染中，包括使用原代淋巴细胞的感染，Y 712 A突变体的生长与Nef阴性病毒一样受损，EnvY 712 A/Delta-Nef组合突变体几乎完全缺陷。在使用CD 4阳性HeLa细胞的单轮感染中，EnvY 712 A突变损害了感染性，而Nef保留了在EnvY 712 A背景下增强感染性的能力。EnvY 712和Nef是从HEK 293 T或MT4细胞产生的病毒体的最佳感染性所需的，但只有当病毒体从MT4细胞产生时，这些序列才是Env的最佳掺入所需的。尽管从293 T细胞产生的病毒中Env的野生型水平，但EnvY 712 A和Delta-Nef突变体进入靶细胞的能力受损。我们的结论是，膜近端酪氨酸为基础的分选基序的gp 41 Env是，像Nef，重要的最佳病毒感染性，并在MT4 T细胞的情况下，病毒粒子纳入Env。Nef不需要Y 712 XXL基序来增强病毒感染性。EnvY 712和Nef各自独立于病毒体的Env含量影响病毒进入的效率的发现表明，两种病毒蛋白质都参与影响形态发生以产生最大融合病毒的运输事件。
The membrane-proximal tyrosine-based sorting motif in the cytoplasmic domain of the human immunodeficiency virus type 1 Env glycoprotein is important for endocytosis from the plasma membrane, basolateral targeting of viral budding in polarized epithelial cells, and polarized budding from a localized region of the lymphocyte plasma membrane. To study the role of the Env sorting motif (Y712XXL) in infectivity, the incorporation of Env into virions, and viral entry, we disrupted the motif with a tyrosine-to-alanine substitution. To investigate the relationship between the Env sorting motif and the enhancement of infectivity by Net, the EnvY712A substitution was made in both Nef-positive and Nef-negative backgrounds. In spreading infections, including those using primary lymphocytes, the growth of the Y712A mutant was as impaired as Nef-negative virus, and the EnvY712A/Delta-Nef combination mutant was almost completely defective. In single-round infections using CD4-positive HeLa cells, the EnvY712A mutation impaired infectivity, and Nef retained the ability to enhance the infectivity in the context of EnvY712A. EnvY712 and Nef were required for the optimal infectivity of virions produced from either HEK293T or MT4 cells, but these sequences were required for the optimal incorporation of Env only when virions were produced from MT4 cells. Despite the wild-type levels of Env in viruses produced from 293T cells, the entry of the EnvY712A and Delta-Nef mutants into target cells was impaired. We conclude that the membrane-proximal tyrosine-based sorting motif of gp41 Env is, like Nef, important for optimal viral infectivity and, in the case of MT4 T cells, virion incorporation of Env. Nef does not require the Y712XXL motif to enhance viral infectivity. The finding that EnvY712 and Nef each affect the efficiency of viral entry independently of the Env content of virions suggests that both viral proteins are involved in trafficking events that influence morphogenesis to produce maximally fusogenic virus.