Hypervariable region 1 sequence stability during hepatitis C virus replication in chimpanzees
Hypervariable region 1 sequence stability during hepatitis C virus replication in chimpanzees
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DOI：
10.1128/jvi.74.7.3058-3066.2000
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发表时间：
2000-04-01
影响因子：
5.4
通讯作者：
Thomas, DL
中科院分区：
文献类型：
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作者：
Ray, SC;Mao, Q;Thomas, DL
假定的丙型肝炎病毒（HCV）包膜2 （E2）基因包含一个称为高变区1 （HVR1）的高度可变区域。我们假设这种遗传变异是由免疫选择压力驱动的，而不是代表在相对较少功能约束的区域中随机突变的积累。为了验证这一假设，我们检查了8只黑猩猩的人类接种物的E2序列，这些黑猩猩的繁殖率（偶然突变的机会）与人类相似。研究人员从一个人（接种物）和8只连续感染的黑猩猩中的6只身上提取急性期血浆样本。对每个克隆的33个cdna进行了异质双链-单链构象多态性联合检测，以评估准物种复杂性，并优化选择具有独特凝胶转移模式（克隆型）的克隆进行测序。黑猩猩的HCV序列多样性明显低于人类，在8次连续传代中，每种动物的大多数克隆型序列没有变化。同样，黑猩猩的蛋白质序列改变（非同义）替换率比人类低。这些发现表明，非同义突变表明选择压力，而不是HCV复制的偶然结果。
The putative envelope 2 (E2) gene of hepatitis C virus (HCV) contains a highly variable region referred to as hypervariable region 1 (HVR1). We hypothesized that this genetic variability is driven by immune selection pressure, rather than representing the accumulation of random mutations in a region with relatively little functional constraint. To test this hypothesis, we examined the E2 sequence of a human inoculum that was passaged through eight chimpanzees, which appear to have a replicative rate (opportunity for chance mutation) similar to that of humans. Acute-phase plasma samples from a human (the inoculum) and six of eight serially infected chimpanzees were studied. For each, 33 cloned cDNAs were examined by a combined hetero-duplex-single-stranded conformational polymorphism assay to assess quasispecies complexity and optimize selection of clones with unique gel shift patterns (clonotypes) for sequencing. The sequence diversity of HCV was significantly lower in the chimpanzees than in the humans, and during eight serial passages there was no change in the sequence of the majority clonotype from each animal examined. Similarly, the rates of protein sequence altering (nonsynonymous) substitution were lower in the chimpanzees than in the humans. These findings demonstrate that nonsynonymous mutations indicate selection pressure rather than being an incidental result of HCV replication.