Dissection of a circumscribed recombination hot spot in HIV-1 after a single infectious cycle
Dissection of a circumscribed recombination hot spot in HIV-1 after a single infectious cycle
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DOI：
10.1074/jbc.m505457200
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发表时间：
2006-02-03
影响因子：
4.8
通讯作者：
Negroni, M
中科院分区：
文献类型：
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作者：
Galetto, R;Giacomoni, VR;Negroni, M
重组是 1 型人类免疫缺陷病毒 (HIV-1) 群体遗传异质性的主要来源。产生重组病毒的主要机制是逆转录过程中基因组RNA的两个拷贝之间的拷贝选择过程。我们之前在培养细胞感染一个周期后发现了 gp120 基因内的重组热点，对应于 RNA 发夹的顶部。在这里，我们确定热区被限制在位于茎下降链中的 18 个核苷酸，遵循逆转录的意义。对于在该区域观察到的高重组率，三个因素似乎很重要，尽管程度不同。 RNA 结构中热序列的位置似乎至关重要，因为改变其在该结构中的位置会引发高达 20 倍的重组差异。另一个关键因素是在转移区域中供体和受体RNA之间存在完全相同的序列，因为热点中的单核苷酸或双核苷酸差异足以几乎完全消除该区域中的重组。最后，热区的一级结构也影响重组，尽管影响仅在 2-3 倍范围内。总而言之，这些结果首次对受感染细胞中的热点进行了分子解剖，并表明有几个因素有助于优先复制选择位点的产生。
Recombination is a major source of genetic heterogeneity in the human immunodeficiency virus type 1 (HIV-1) population. The main mechanism responsible for the generation of recombinant viruses is a process of copy choice between the two copies of genomic RNA during reverse transcription. We previously identified, after a single cycle of infection of cells in culture, a recombination hot spot within the gp120 gene, corresponding to the top portion of a RNA hairpin. Here, we determine that the hot region is circumscribed to 18 nucleotides located in the descending strand of the stem, following the sense of reverse transcription. Three factors appeared to be important, albeit at different extents, for the high rate of recombination observed in this region. The position of the hot sequence in the context of the RNA structure appears crucial, because changing its location within this structure triggered differences in recombination up to 20-fold. Another pivotal factor is the presence of a perfectly identical sequence between donor and acceptor RNA in the region of transfer, because single or double nucleotide differences in the hot spot were sufficient to almost completely abolish recombination in the region. Last, the primary structure of the hot region also influenced recombination, although with effects only in the 2-3-fold range. Altogether, these results provide the first molecular dissection of a hot spot in infected cells and indicate that several factors contribute to the generation of a site of preferential copy choice.