Loemba Hugues, Brenner Bluma, Parniak Michael A, Ma'ayan Shlomo, Spira Bonnie, Moisi Daniela, Oliveira Maureen, Detorio Mervi, Wainberg Mark A
McGill University AIDS Centre, Lady Davis Institute-Jewish General Hospital, Montreal, Quebec, Canada.
Antimicrob Agents Chemother. 2002 Jul;46(7):2087-94. doi: 10.1128/AAC.46.7.2087-2094.2002.
We sequenced and phylogenetically analyzed the reverse transcriptase (RT) region of five human immunodeficiency virus type 1 isolates from treatment-naive Ethiopian émigrés to Israel. Heteroduplex mobility assays were performed to confirm the clade C status of env genomic regions. The RT sequences showed that the strains clustered phylogenetically with clade C viruses, and a KVEQ-specific motif of silent mutations (amino acids 65, 106, 138, and 161, respectively) at resistance sites was present in the polymerase region of all studied Ethiopian isolates and subtype C reference strains. In addition, many other silent mutations were observed in the clade C viruses at various resistance sites. In general, the Ethiopian isolates were more closely related genotypically to a clade C reference strain from Botswana (southern Africa) than to previously sequenced Ethiopian reference strains. Genotypic analysis showed that two Ethiopian isolates naturally harbored the mutations K70R and G190A associated with resistance to ZDV and nonnucleoside reverse transcriptase inhibitors, respectively. Phenotypic assays revealed that the K70R substitution in this context did not reduce susceptibility to ZDV, whereas the G190A substitution resulted in high-level resistance to nevirapine (NVP). Moreover, variants resistant to NVP, delavirdine (DLV), and efavirenz (EFV) were more rapidly selected at lower drug doses culture with clade C than with clade B wild-type isolates. In the case of subtype C, selection with NVP and/or EFV led to the appearance of several previously unseen mutations in RT, i.e., V106M and S98I, as well as other mutations that have been previously reported (e.g., K103N, V106A, V108I, and Y181C). After selection with DLV, a polymorphism, A62A, initially observed in the Ethiopian isolate 4762, mutated to A62V; the latter is a secondary substitution associated with multidrug resistance against nucleoside RT inhibitors. Phenotypic analysis of clade C mutants selected against NVP, DLV, and EFV revealed broad cross-resistance, particularly in regard to NVP and DLV. These findings suggest that RT genotypic diversity may influence the emergence of drug resistance.
我们对来自埃塞俄比亚、初治且移民至以色列的5株人类免疫缺陷病毒1型（HIV-1）分离株的逆转录酶（RT）区域进行了测序和系统发育分析。进行异源双链迁移率分析以确认env基因组区域的C亚型状态。RT序列显示，这些毒株在系统发育上与C亚型病毒聚类，并且在所有研究的埃塞俄比亚分离株和C亚型参考毒株的聚合酶区域中，存在耐药位点处沉默突变的KVEQ特异性基序（分别位于氨基酸65、106、138和161位）。此外，在C亚型病毒的各种耐药位点还观察到许多其他沉默突变。总体而言，埃塞俄比亚分离株在基因型上与来自博茨瓦纳（非洲南部）的C亚型参考毒株的关系，比与先前测序的埃塞俄比亚参考毒株的关系更为密切。基因型分析表明，两株埃塞俄比亚分离株天然携带分别与对齐多夫定（ZDV）和非核苷类逆转录酶抑制剂耐药相关的K70R和G190A突变。表型分析显示，在此背景下K70R替代并未降低对ZDV的敏感性，而G190A替代导致对奈韦拉平（NVP）产生高水平耐药。此外，与C亚型野生型分离株相比，在较低药物剂量培养时，对NVP、地拉韦啶（DLV）和依非韦伦（EFV）耐药的变异株在与C亚型培养时更快速地被选择出来。对于C亚型，用NVP和/或EFV进行选择导致在RT中出现几个先前未见的突变，即V106M和S98I，以及其他先前已报道的突变（例如K103N、V106A、V108I和Y181C）。在用DLV进行选择后，最初在埃塞俄比亚分离株4762中观察到的多态性A62A突变为A62V；后者是与对核苷类RT抑制剂多药耐药相关的二次替代。针对NVP、DLV和EFV选择的C亚型突变体的表型分析显示出广泛的交叉耐药性，特别是对于NVP和DLV。这些发现表明RT基因型多样性可能影响耐药性的出现。
