Retroviral DNA integration: viral and cellular determinants of target-site selection.
Retroviral DNA integration: viral and cellular determinants of target-site selection.
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逆转录病毒DNA整合：靶位点选择的病毒和细胞决定因素。
DOI：
10.1371/journal.ppat.0020060
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发表时间：
2006-06
期刊：
影响因子：
6.7
通讯作者：
Bushman, Frederic D
中科院分区：
文献类型：
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作者：
Lewinski, Mary K;Yamashita, Masahiro;Emerman, Michael;Ciuffi, Angela;Marshall, Heather;Crawford, Gregory;Collins, Francis;Shinn, Paul;Leipzig, Jeremy;Hannenhalli, Sridhar;Berry, Charles C;Ecker, Joseph R;Bushman, Frederic D
逆转录病毒在感染细胞染色体中病毒DNA整合位点的偏好上有所不同。人类免疫缺陷病毒（HIV）优先整合在活跃的转录单元内，而鼠白血病病毒（MLV）则优先整合在转录起始位点和CpG岛附近。我们利用将MLV基因替换其HIV对应基因的HIV嵌合体研究了整合位点选择的病毒决定因素。我们发现将MLV整合酶（IN）编码区转入HIV（构建HIVmIN）使得该杂合病毒以接近MLV的特异性进行整合。添加MLV的gag基因（构建HIVmGagmIN）进一步增加了靶位点选择与MLV的相似性。仅含MLV Gag的嵌合病毒（HIVmGag）显示出不同于HIV和MLV的靶向偏好，这进一步表明Gag蛋白在靶向以及整合酶中都起作用。我们还报道了一项全基因组分析，表明MLV（而非HIV）倾向于在DNA酶I超敏感位点（即±1kb）附近整合，并且HIVmIN和HIVmGagmIN也倾向于在这些区域附近整合。这些发现表明整合酶是整合特异性的主要病毒决定因素；它们还揭示了Gag衍生蛋白的新作用，并强化了基于病毒整合酶蛋白与宿主蛋白连接的整合靶向模型。
逆转录病毒复制周期中的一个必要步骤是将病毒基因组的DNA拷贝整合到宿主细胞染色体中。近期研究表明，人类免疫缺陷病毒（HIV）和鼠白血病病毒（MLV）倾向于在不同的染色体特征附近整合。HIV优先靶向活跃基因，而MLV则更喜欢在基因转录起始位点附近整合。作者通过用MLV片段替代的HIV衍生物研究了整合 - 靶位点选择，以确定哪些病毒蛋白负责整合 - 靶向偏好。他们发现病毒整合酶蛋白是整合位点选择的主要决定因素，可能是通过其与偏好基因组区域附近结合的细胞蛋白的连接。此外，病毒结构多聚蛋白Gag的成分似乎也参与靶向。这些发现为参与指导整合位点选择的病毒蛋白提供了一个功能图谱。
Retroviruses differ in their preferences for sites for viral DNA integration in the chromosomes of infected cells. Human immunodeficiency virus (HIV) integrates preferentially within active transcription units, whereas murine leukemia virus (MLV) integrates preferentially near transcription start sites and CpG islands. We investigated the viral determinants of integration-site selection using HIV chimeras with MLV genes substituted for their HIV counterparts. We found that transferring the MLV integrase (IN) coding region into HIV (to make HIVmIN) caused the hybrid to integrate with a specificity close to that of MLV. Addition of MLV gag (to make HIVmGagmIN) further increased the similarity of target-site selection to that of MLV. A chimeric virus with MLV Gag only (HIVmGag) displayed targeting preferences different from that of both HIV and MLV, further implicating Gag proteins in targeting as well as IN. We also report a genome-wide analysis indicating that MLV, but not HIV, favors integration near DNase I–hypersensitive sites (i.e., +/− 1 kb), and that HIVmIN and HIVmGagmIN also favored integration near these features. These findings reveal that IN is the principal viral determinant of integration specificity; they also reveal a new role for Gag-derived proteins, and strengthen models for integration targeting based on tethering of viral IN proteins to host proteins. A required step in the replication cycle of retroviruses is the integration of a DNA copy of the viral genome into a host cell chromosome. Recent studies have shown that human immunodeficiency virus (HIV) and murine leukemia virus (MLV) favor integration near different chromosomal features. HIV preferentially targets active genes, while MLV prefers integration near start sites of gene transcription. The authors investigated integration-target site–selection by HIV derivatives substituted with segments of MLV to determine which viral proteins are responsible for integration-targeting preferences. They found that the viral integrase protein is the dominant determinant of integration-site selection, probably through its tethering to cellular proteins bound near preferred genomic regions. In addition, components of the viral structural polyprotein, Gag, appear to be involved in targeting. These findings provide a functional map of the viral proteins involved in directing integration-site selection.