Cutillas Vincent, Mesplede Thibault, Anstett Kaitlin, Hassounah Said, Wainberg Mark A
McGill University AIDS Centre, Lady Davis Institute for Medical Research, Jewish General Hospital, Montréal, Québec, Canada Department of Microbiology and Immunology, McGill University, Montréal, Québec, Canada.
Department of Microbiology and Immunology, McGill University, Montréal, Québec, Canada.
Antimicrob Agents Chemother. 2015 Jan;59(1):310-6. doi: 10.1128/AAC.04274-14. Epub 2014 Oct 27.
Clinical studies have shown that integrase strand transfer inhibitors (INSTIs) can be used effectively against HIV-1 infection. To date, no resistance substitution has been found in INSTI-naive patients treated with the new integrase inhibitor dolutegravir (DTG). In a recent selection study with DTG, using a virus bearing the H51Y substitution in integrase, the emergence of an R to K substitution at position 262 (R262K) was observed. We characterized this double mutant with respect to integrase strand transfer activity and susceptibility to DTG both biochemically and in tissue culture. We showed that the addition of R262K to H51Y decreased recombinant integrase strand transfer activity but improved integrase DNA-binding affinity, compared to wild-type or H51Y-containing enzymes. The defect in strand transfer activity did not translate into a decrease in HIV-1 infectivity. The combination of H51Y and R262K substitutions slightly decreased susceptibility to DTG (fold change = 1.87) in cell-based resistance assays. Although viral replication was not affected and enzyme efficiency was impaired by the addition of R262K to H51Y, there was an overall increase in the level of biochemical drug resistance against DTG. Our findings suggest that the R at position 262 plays an important role in DNA binding.
临床研究表明，整合酶链转移抑制剂（INSTIs）可有效对抗HIV-1感染。迄今为止，在接受新型整合酶抑制剂度鲁特韦（DTG）治疗的初治患者中尚未发现耐药性替代突变。在最近一项使用整合酶中携带H51Y替代突变的病毒进行的DTG选择研究中，观察到在第262位出现了从R到K的替代突变（R262K）。我们从生化和组织培养两方面对这种双突变体的整合酶链转移活性和对DTG的敏感性进行了表征。我们发现，与野生型或含H51Y的酶相比，在H51Y基础上添加R262K会降低重组整合酶链转移活性，但会提高整合酶与DNA的结合亲和力。链转移活性的缺陷并未转化为HIV-1感染性的降低。在基于细胞的耐药性试验中，H51Y和R262K替代突变的组合使对DTG的敏感性略有降低（倍数变化 = 1.87）。尽管病毒复制未受影响，且在H51Y基础上添加R262K会损害酶的效率，但对DTG的生化耐药水平总体上有所增加。我们的研究结果表明，第262位的R在DNA结合中起重要作用。
