APOBEC3F and APOBEC3G Inhibit HIV-1 DNA Integration by Different Mechanisms
APOBEC3F and APOBEC3G Inhibit HIV-1 DNA Integration by Different Mechanisms
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DOI：
10.1128/jvi.02358-09
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发表时间：
2010-05-01
影响因子：
5.4
通讯作者：
Pathak, Vinay K.
中科院分区：
文献类型：
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作者：
Mbisa, Jean L.;Bu, Wei;Pathak, Vinay K.
APOBEC 3F（A3 F）和APBOBEC 3G（A3 G）都是宿主限制性因子，可以有效抑制人类免疫缺陷病毒1型（HIV-1）复制。它们的抗病毒活性至少部分由胞苷脱氨基介导，这导致病毒基因组的致命突变。我们最近发现A3 G阻断病毒正链DNA转移并抑制原病毒在宿主基因组中的建立（J. L.姆比萨河巴尔，J. A.托马斯，N.万德格拉夫岛J. Dorweiler，E. S. Svarovskaia，W. L.布朗湖，澳-地M.曼斯基河戈雷利克河S.哈里斯，A. Engelman和V.K. Pathak，J. Virol. 81：7099-7110，2007）。在这里，我们调查是否A3 F同样干扰HIV-1前病毒的形成。我们观察到A3 F和A3 G都抑制病毒DNA合成和整合，但A3 F在阻止病毒DNA整合方面比A3 G更有效。我们进一步研究了A3 F和A3 G阻断病毒DNA整合的机制，通过使用Southern印迹分析分析它们对病毒cDNA加工的影响。A3 G在3'长末端重复序列（3'-LTR）的病毒U 5末端产生6-bp延伸，这是整合的不良底物;相反，A3 F通过减少病毒DNA在U 5和U3末端的3'加工来抑制病毒DNA整合。此外，我们证明了功能性C末端催化结构域对于A3 G比A3 F在阻断HIV-1前病毒形成方面的功能更重要。最后，我们表明A3 F对病毒3 '-LTR双链DNA（dsDNA）寡核苷酸模板具有比A3 G更大的结合亲和力。综合这些结果，我们证明了A3 F用于防止HIV-1病毒DNA整合的机制与A3 G不同，并且它们的靶特异性和/或它们对dsDNA的亲和力可能有助于它们不同的机制。
APOBEC3F (A3F) and APBOBEC3G (A3G) both are host restriction factors that can potently inhibit human immunodeficiency virus type 1 (HIV-1) replication. Their antiviral activities are at least partially mediated by cytidine deamination, which causes lethal mutations of the viral genome. We recently showed that A3G blocks viral plus-strand DNA transfer and inhibits provirus establishment in the host genome (J. L. Mbisa, R. Barr, J. A. Thomas, N. Vandegraaff, I. J. Dorweiler, E. S. Svarovskaia, W. L. Brown, L. M. Mansky, R. J. Gorelick, R. S. Harris, A. Engelman, and V. K. Pathak, J. Virol. 81: 7099-7110, 2007). Here, we investigated whether A3F similarly interferes with HIV-1 provirus formation. We observed that both A3F and A3G inhibit viral DNA synthesis and integration, but A3F is more potent than A3G in preventing viral DNA integration. We further investigated the mechanisms by which A3F and A3G block viral DNA integration by analyzing their effects on viral cDNA processing using Southern blot analysis. A3G generates a 6-bp extension at the viral U5 end of the 3' long terminal repeat (3'-LTR), which is a poor substrate for integration; in contrast, A3F inhibits viral DNA integration by reducing the 3' processing of viral DNA at both the U5 and U3 ends. Furthermore, we demonstrated that a functional C-terminal catalytic domain is more critical for A3G than A3F function in blocking HIV-1 provirus formation. Finally, we showed that A3F has a greater binding affinity for a viral 3'-LTR double-stranded DNA (dsDNA) oligonucleotide template than A3G. Taking these results together, we demonstrated that mechanisms utilized by A3F to prevent HIV-1 viral DNA integration were different from those of A3G, and that their target specificities and/or their affinities for dsDNA may contribute to their distinct mechanisms.