HIV-1 Cell-Free and Cell-to-Cell Infections Are Differentially Regulated by Distinct Determinants in the Env gp41 Cytoplasmic Tail
HIV-1 Cell-Free and Cell-to-Cell Infections Are Differentially Regulated by Distinct Determinants in the Env gp41 Cytoplasmic Tail
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DOI：
10.1128/jvi.00655-15
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发表时间：
2015-09-01
影响因子：
5.4
通讯作者：
Chen, Benjamin K.
中科院分区：
文献类型：
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作者：
Durham, Natasha D.;Chen, Benjamin K.
HIV-1包膜（Env）糖蛋白在CD 4（+）T细胞的无细胞和细胞间感染期间介导病毒进入。Env的高度保守的长胞质尾区（CT）以细胞类型依赖性方式对于无细胞病毒的最佳感染性是必需的。为了探索CT在细胞间感染中的作用，我们测试了CT区域中维持或减弱无细胞感染的一组突变，以研究CT的功能在无细胞和细胞间感染期间是否保守。测试的突变包括gp 41 CT中结构基序的截短和先前描述为破坏无细胞病毒感染性的慢病毒裂解肽3（LLP-3）中的两个点突变。我们发现，28至43个氨基酸（aa）的小截短或两个LLP-3点突变，YW_SL和LL_RQ，严重损害单轮无细胞感染性相对于野生型全长CT的10倍或更多。这些突变体在细胞间感染测定中显示出适度的2倍减少。相反，93至124个氨基酸的大截短严重损害细胞间感染性20倍或更多，同时导致在293 T细胞中产生的无细胞病毒颗粒的感染性增加50%。中间截断的46至90 aa表现出深刻的损害这两种模式的感染。我们的研究结果表明，Env支持无细胞和细胞间感染的能力在遗传上是不同的。这些差异对于大CT截短突变体是细胞类型依赖性的。此外，LLP-3中的点突变体可以维持原代CD 4（+）T细胞中从细胞到细胞的多轮增殖。重要信息尽管在无细胞感染的背景下进行了广泛的研究，但对HIV Env gp 41 CT的功能仍然知之甚少。我们已经确定了gp 41 CT的结构域负责罢工的选择性缺陷，无论是无细胞或细胞对细胞的感染。这些差异可能反映了CT对细胞相关与颗粒相关Env的不同内在调节影响，或与宿主或病毒蛋白的差异相互作用。我们的研究结果为gp 41 CT在无细胞和细胞间HIV-1感染中的关键调控潜力提供了新的见解，特别是对于HIV-1短截短突变体，
The HIV-1 envelope (Env) glycoprotein mediates viral entry during both cell-free and cell-to-cell infection of CD4(+) T cells. The highly conserved long cytoplasmic tail (CT) of Env is required in a cell type-dependent manner for optimal infectivity of cell-free virus. To probe the role of the CT in cell-to-cell infection, we tested a panel of mutations in the CT region that maintain or attenuate cell-free infection to investigate whether the functions of the CT are conserved during cell-free and cell-to-cell infection. The mutations tested included truncations of structural motifs in the gp41 CT and two point mutations in lentiviral lytic peptide 3 (LLP-3) previously described as disrupting the infectivity of cell-free virus. We found that small truncations of 28 to 43 amino acids (aa) or two LLP-3 point mutations, YW_SL and LL_RQ, severely impaired single-round cell-free infectivity 10-fold or more relative to wild-type full-length CT. These mutants showed a modest 2-fold reduction in cell-to-cell infection assays. Conversely, large truncations of 93 to 124 aa severely impaired cell-to-cell infectivity 20-fold or more while resulting in a 50% increase in infectivity of cell-free viral particles when produced in 293T cells. Intermediate truncations of 46 to 90 aa showed profound impairment of both modes of infection. Our results show that the abilities of Env to support cell-free and cell-to-cell infection are genetically distinct. These differences are cell type dependent for large-CT-truncation mutants. Additionally, point mutants in LLP-3 can maintain multiround propagation from cell-to-cell in primary CD4(+) T cells.IMPORTANCEThe functions of HIV Env gp41 CT remain poorly understood despite being widely studied in the context of cell-free infection. We have identified domains of the gp41 CT responsible for striking selective deficiencies in either cell-free or cell-to-cell infectivity. These differences may reflect a different intrinsic regulatory influence of the CT on cell-associated versus particle-associated Env or differential interaction with host or viral proteins. Our findings provide novel insight into the key regulatory potential of the gp41 CT in cell-free and cell-to-cell HIV-1 infection, particularly for short-truncation mutants of