Expression Level of HIV-1 Vif Can Be Fluctuated by Natural Nucleotide Variations in the vif-Coding and Regulatory SA1D2prox Sequences of the Proviral Genome
Expression Level of HIV-1 Vif Can Be Fluctuated by Natural Nucleotide Variations in the vif-Coding and Regulatory SA1D2prox Sequences of the Proviral Genome
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DOI：
10.3389/fmicb.2019.02758
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发表时间：
2019-11-28
影响因子：
5.2
通讯作者：
Nomaguchi, Masako
中科院分区：
文献类型：
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作者：
Doi, Naoya;Koma, Takaaki;Nomaguchi, Masako
Vif是HIV-1在天然靶细胞中复制所必需的，通过抵消宿主限制因子APOBEC 3（A3）蛋白。我们最近证明，Vif表达水平可以通过HIV-1基因组SA 1D 2 prox内自然发生的单核苷酸变异来改变。我们还发现vif/vpr mRNA的水平呈负相关。虽然氨基酸序列本身对功能性至关重要，但由其编码区中的信号序列调节的Vif表达水平可能也很重要。在vpr表达的区域有两个剪接位点。为了揭示Vif表达水平的可能波动，我们使用具有不同抗A3活性的HIV-1亚型B和C通过嵌合方法检测了SA 1D 2 prox和vif基因。在本报告中，产生了亚型B骨架中携带SA 1D 2 prox/vif嵌合序列和vif编码区内的嵌合序列的重组克隆。其中，含有C亚型vif基因编码序列的克隆，尤其是其3 '端，vif/Vif的表达水平降低，vpr/Vpr的表达水平升高。与降低的vif/Vif水平的克隆生长相似或稍好于一个亲本克隆在弱A3 G阳性细胞，但更差的A3 G高表达细胞。还测试了具有该性质的三个克隆的A3降解活性。其中一个克隆似乎除了表达vif/Vif的能力差之外还有一些缺陷。综上所述，我们的研究结果表明，SA 1D 2 prox和VIF编码区的自然变异可以改变VIF的表达水平，并影响HIV-1的复制潜力。
Vif is required for HIV-1 replication in natural target cells by counteracting host restriction factors, APOBEC3 (A3) proteins. We recently demonstrated that Vif expression level can be changed by naturally occurring single-nucleotide variations within SA1D2prox of the HIV-1 genome. We also found that levels for vif/vpr mRNAs are inversely correlated. While amino acid sequence per se is critical for functionality, Vif expression level modulated by signal sequences in its coding region is likely to be important as well. There are two splicing sites in the region involved in vpr expression. To reveal possible fluctuations of Vif-expression level, we examined SA1D2prox and vif gene by chimeric approaches using HIV-1 subtypes B and C with distinct anti-A3 activity. In this report, recombinant clones in subtype B backbone carrying chimeric sequences with respect to SA1D2prox/vif and those within the vif-coding region were generated. Of these, clones containing vif-coding sequence of subtype C, especially its 3 ' region, expressed vif/Vif at a decreased level but did at an increased level for vpr/Vpr. Clones with reduced vif/Vif level grew similarly or slightly better than a parental clone in weakly A3G-positive cells but more poorly in highly A3G-expressing cells. Three clones with this property were also tested for their A3-degrading activity. One of the clones appeared to have some defect in addition to the poor ability to express vif/Vif. Taken all together, our results show that natural variations in the SA1D2prox and vif-coding region can change the Vif-expression level and affect the HIV-1 replication potential.