Natural Single-Nucleotide Variations in the HIV-1 Genomic SA1prox Region Can Alter Viral Replication Ability by Regulating Vif Expression Levels
Natural Single-Nucleotide Variations in the HIV-1 Genomic SA1prox Region Can Alter Viral Replication Ability by Regulating Vif Expression Levels
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DOI：
10.1128/jvi.02939-15
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发表时间：
2016-05-01
影响因子：
5.4
通讯作者：
Adachi, Akio
中科院分区：
文献类型：
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作者：
Nomaguchi, Masako;Doi, Naoya;Adachi, Akio
我们以前发现，位于剪接受体1（SA 1 prox）在HIV-1基因组中的近端区域内的天然单核苷酸变异可以改变病毒的复制潜力和mRNA表达模式，特别是vif mRNA水平。在这里，我们研究了病毒复制能力的改变在SA 1 prox的核苷酸序列变异的病毒学和分子基础。与我们先前的发现一致，变体克隆确实以不同水平表达Vif，并且在具有不同APOBEC 3G表达水平的细胞中特异性生长。在HIV-2 SA 1 prox中发现的自然变异也观察到类似的效果，这表明SA 1 prox序列的重要性。为了确定调节HIV-1 Vif表达的关键核苷酸，检查了HIV序列纲要数据库中新发现的天然SA 1 prox变异对Vif mRNA/Vif蛋白水平的影响。发现九个变异中的七个产生比野生型NL 4 -3更低、更高或更过量水平的Vif。不同的Vif水平的变化的组合实验表明，变化相互影响的Vif转录生产。虽然Vif的低生产者和高生产者以APOBEC 3G依赖性方式生长，但由于单循环感染性和/或病毒体生产水平的缺陷，过量表达者总是显示出生长受阻的表型。过量表达者的表型主要不是由于达特或Rev表达不足，尽管SA 1 prox变异改变了总体HIV-1 mRNA表达模式。总的来说，我们的研究结果表明，HIV SA 1 prox调节Vif表达水平，并表明SA 1 prox和病毒适应/进化之间的关系，因为变化自然发生。
We previously found that natural single-nucleotide variations located within a proximal region of splicing acceptor 1 (SA1prox) in the HIV-1 genome could alter the viral replication potential and mRNA expression pattern, especially the vif mRNA level. Here, we studied the virological and molecular basis of nucleotide sequence variations in SA1prox for alterations of viral replication ability. Consistent with our previous findings, variant clones indeed expressed Vif at different levels and grew distinctively in cells with various APOBEC3G expression levels. Similar effects were observed for natural variations found in HIV-2 SA1prox, suggesting the importance of the SA1prox sequence. To define nucleotides critical for the regulation of HIV-1 Vif expression, effects of natural SA1prox variations newly found in the HIV Sequence Compendium database on vif mRNA/Vif protein levels were examined. Seven out of nine variations were found to produce Vif at lower, higher, or more excessive levels than wild-type NL4-3. Combination experiments of variations giving distinct Vif levels suggested that the variations mutually affected vif transcript production. While low and high producers of Vif grew in an APOBEC3G-dependent manner, excessive expressers always showed an impeded growth phenotype due to defects in single-cycle infectivity and/or virion production levels. The phenotype of excessive expressers was not due primarily to inadequate expression of Tat or Rev, although SA1prox variations altered the overall HIV-1 mRNA expression pattern. Collectively, our results demonstrate that HIV SA1prox regulates Vif expression levels and suggest a relationship between SA1prox and viral adaptation/evolution given that variations occurred naturally.