Mg2+ dependency of HIV-1 reverse transcription, inhibition by nucleoside analogues and resistance.
Mg2+ dependency of HIV-1 reverse transcription, inhibition by nucleoside analogues and resistance.
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DOI：
10.1093/nar/gkj411
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发表时间：
2006
影响因子：
14.9
通讯作者：
Marquet, R
中科院分区：
文献类型：
--
作者：
Goldschmidt, V;Didierjean, J;Ehresmann, B;Ehresmann, C;Isel, C;Marquet, R
金属离子对HIV-1逆转录酶（RT）的DNA聚合酶和RNase H活性是必需的。RT研究通常在6-8 mM Mg 2+下进行，尽管体内浓度可能低至0.2 mM。我们研究了MgCl 2和ATP对HIV-1 RT的DNA聚合酶和RNA酶H活性的影响，在低Mg ~（2+）浓度下，尽管在这样的条件下固有聚合酶活性显著降低，但天然模板的逆转录强烈增加。低浓度的Mg ~（2+）影响RNA的稳定性，并间接降低RNA酶H对RNA的降解。减少的RNA降解防止了模板和引物链的过早解离，否则会产生死端DNA产物。此外，低Mg 2+显着降低了NRTI掺入DNA和增加核苷酸切除AZT耐药RT。后者的效果也很可能是由于减少切割的RNA模板。因此，不同细胞类型之间或细胞周期期间游离Mg 2+浓度的差异可能强烈影响HIV-1复制及其抑制。
Metal ions are essential for DNA polymerase and RNase H activities of HIV-1 reverse transcriptase (RT). RT studies are routinely performed at 6–8 mM Mg2+, despite the fact that the in vivo concentration might be as low as 0.2 mM. We studied the influence of MgCl2 and ATP, which likely binds a significant fraction of the magnesium pool in vivo, on the DNA polymerase and RNase H activities of HIV-1 RT, its inhibition by nucleoside RT inhibitors (NRTIs) and primer unblocking by AZT-resistant RT. At low Mg2+ concentration, reverse transcription of a natural template strongly increased despite a dramatically reduced intrinsic polymerase activity under such conditions. Low Mg2+ concentrations affected the RNA stability and indirectly decreased its degradation by the RNase H activity. The reduced RNA degradation prevented premature dissociation of the template and primer strands that otherwise generated dead-end DNA products. In addition, low Mg2+ dramatically decreased the incorporation of NRTIs into DNA and increased nucleotide excision by AZT-resistant RT. The latter effect is also most likely owing to the diminished cleavage of the RNA template. Thus, differences in the free Mg2+ concentration between different cell types or during the cell cycle might strongly affect HIV-1 replication and its inhibition.
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