HIV Drug Resistance Program, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702, USA.
Proc Natl Acad Sci U S A. 2013 Sep 3;110(36):14747-52. doi: 10.1073/pnas.1305066110. Epub 2013 Aug 19.
Integration of the DNA copy of the HIV-1 genome into a host chromosome is required for viral replication and is thus an important target for antiviral therapy. The HIV-encoded enzyme integrase (IN) catalyzes two essential steps: 3' processing of the viral DNA ends, followed by the strand transfer reaction, which inserts the viral DNA into host DNA. Raltegravir binds to IN and blocks the integration of the viral DNA. Using the Rous sarcoma virus-derived vector RCAS, we previously showed that mutations that cause one viral DNA end to be defective for IN-mediated integration led to abnormal integrations in which the provirus had one normal and one aberrant end, accompanied by rearrangements in the host genome. On the basis of these results, we expected that suboptimal concentrations of IN inhibitors, which could block one of the ends of viral integration, would lead to similar aberrant integrations. In contrast to the proviruses from untreated cells, which were all normal, ∼10-15% of the proviruses isolated after treatment with a suboptimal dose of raltegravir were aberrant. The aberrant integrations were similar to those seen in the RCAS experiments. Most of the aberrant proviruses had one normal end and one aberrant end and were accompanied by significant rearrangements in the host genome, including duplications, inversions, deletions and, occasionally, acquisition of sequences from other chromosomes. The rearrangements of the host DNA raise concerns that these aberrant integrations might have unintended consequences in HIV-1-infected patients who are not consistent in following a raltegravir-containing treatment regimen.
HIV-1 基因组的 DNA 拷贝整合到宿主染色体中是病毒复制所必需的，因此是抗病毒治疗的重要靶点。HIV 编码的酶整合酶（IN）催化两个必需步骤：病毒 DNA 末端的 3' 加工，随后是链转移反应，将病毒 DNA 插入宿主 DNA。拉替拉韦结合 IN 并阻断病毒 DNA 的整合。使用 Rous 肉瘤病毒衍生的载体 RCAS，我们之前表明，导致一个病毒 DNA 末端对 IN 介导的整合有缺陷的突变导致异常整合，其中前病毒有一个正常末端和一个异常末端，并伴有宿主基因组的重排。基于这些结果，我们预计 IN 抑制剂的亚最佳浓度，其可以阻断病毒整合的一个末端，将导致类似的异常整合。与未经处理的细胞中的前病毒不同，它们都是正常的，在亚最佳剂量拉替拉韦处理后分离的前病毒中，约 10-15%是异常的。异常整合与 RCAS 实验中观察到的相似。大多数异常前病毒有一个正常末端和一个异常末端，并伴有宿主基因组的显著重排，包括重复、反转、缺失，偶尔还会从其他染色体获得序列。宿主 DNA 的重排引起人们的担忧，即在不坚持使用包含拉替拉韦的治疗方案的 HIV-1 感染患者中，这些异常整合可能会产生意想不到的后果。
