Christopher Bond Life Sciences Center, Department of Molecular Microbiology & Immunology, University of Missouri, School of Medicine, Columbia, MO 65211, USA.
Nucleic Acids Res. 2012 Jan;40(1):345-59. doi: 10.1093/nar/gkr694. Epub 2011 Sep 8.
We report key mechanistic differences between the reverse transcriptases (RT) of human immunodeficiency virus type-1 (HIV-1) and of xenotropic murine leukemia virus-related virus (XMRV), a gammaretrovirus that can infect human cells. Steady and pre-steady state kinetics demonstrated that XMRV RT is significantly less efficient in DNA synthesis and in unblocking chain-terminated primers. Surface plasmon resonance experiments showed that the gammaretroviral enzyme has a remarkably higher dissociation rate (k(off)) from DNA, which also results in lower processivity than HIV-1 RT. Transient kinetics of mismatch incorporation revealed that XMRV RT has higher fidelity than HIV-1 RT. We identified RNA aptamers that potently inhibit XMRV, but not HIV-1 RT. XMRV RT is highly susceptible to some nucleoside RT inhibitors, including Translocation Deficient RT inhibitors, but not to non-nucleoside RT inhibitors. We demonstrated that XMRV RT mutants K103R and Q190M, which are equivalent to HIV-1 mutants that are resistant to tenofovir (K65R) and AZT (Q151M), are also resistant to the respective drugs, suggesting that XMRV can acquire resistance to these compounds through the decreased incorporation mechanism reported in HIV-1.
我们报告了人类免疫缺陷病毒 1 型（HIV-1）和嗜性鼠白血病病毒相关病毒（XMRV）的逆转录酶（RT）之间的关键机制差异，XMRV 是一种能够感染人类细胞的γ逆转录病毒。稳态和预稳态动力学研究表明，XMRV RT 在 DNA 合成和链终止引物的去阻断方面效率明显较低。表面等离子体共振实验表明，γ逆转录病毒酶具有更高的 DNA 解离速率（k（off）），这也导致其比 HIV-1 RT 的持续性更低。错配掺入的瞬态动力学研究表明，XMRV RT 的保真度高于 HIV-1 RT。我们鉴定了一些 RNA 适体，它们能够有效地抑制 XMRV，但不能抑制 HIV-1 RT。XMRV RT 对一些核苷 RT 抑制剂高度敏感，包括易位缺陷 RT 抑制剂，但对非核苷 RT 抑制剂不敏感。我们证明，XMRV RT 突变体 K103R 和 Q190M，相当于对替诺福韦（K65R）和 AZT（Q151M）耐药的 HIV-1 突变体，也对这些药物具有耐药性，这表明 XMRV 可以通过 HIV-1 中报道的降低整合机制获得对这些化合物的耐药性。
