Polymorphisms and Splice Variants Influence the Antiretroviral Activity of Human APOBEC3H
Polymorphisms and Splice Variants Influence the Antiretroviral Activity of Human APOBEC3H
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DOI：
10.1128/jvi.01665-08
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发表时间：
2009-01-01
影响因子：
5.4
通讯作者：
Simon, Viviana
中科院分区：
文献类型：
--
作者：
Harari, Ariana;Ooms, Marcel;Simon, Viviana
人APOBEC 3 H属于有效抑制外源性和内源性逆转录病毒的胞苷脱氨酶的APOBEC 3家族。单核苷酸多态性（SNP）和选择性剪接对人APOBEC 3 H抗逆转录病毒活性的影响目前尚不清楚。在这项研究中，我们表明，APOBEC 3 H转录来自人外周血单核细胞的序列是多态性和可变剪接。我们发现编码SNP簇的APOBEC 3 H变体（G105 R、K121 D和E178 D，hapII-RDD）比野生型APOBEC 3 H（hapI-GKE）更有效地限制人类免疫缺陷病毒1型（HIV-1）。测试的所有APOBEC 3 H变体对HIV-1 Vif具有抗性，HIV-1 Vif是一种有效抵消APOBEC 3G/3F活性的病毒蛋白。APOBEC 3 H的选择性剪接很常见，并产生具有不同C末端区域和不同抗逆转录病毒活性的变体。hapI-GKE的剪接变体显示出广泛的抗病毒活性，而hapII-RDD中的类似剪接事件导致蛋白质均匀且有效地限制病毒感染性（>20倍）。定点诱变鉴定了hapI-GKE中的G105 R和hapII-RDD中的D121 K作为导致抗病毒活性平均额外增加10倍的关键取代。APOBEC 3 H变体具有催化活性，并且与APOBEC 3F类似，有利于GA二核苷酸背景。通过观察到胞苷脱氨酶结构域突变体的限制性降低以及G至A突变与感染性之间的负相关性，表明HIV-1诱变是APOBEC 3 H的一种作用模式。因此，APOBEC 3 H的抗HIV活性似乎受到基因组变异和选择性剪接的组合的调节。由于hapII-RDD在非洲裔人群中的患病率很高，这些发现提出了一些人可能具有有效的以及HIV-1 Vif耐药的细胞内抗病毒防御机制的可能性。
Human APOBEC3H belongs to the APOBEC3 family of cytidine deaminases that potently inhibit exogenous and endogenous retroviruses. The impact of single nucleotide polymorphisms (SNP) and alternative splicing on the antiretroviral activity of human APOBEC3H is currently unknown. In this study, we show that APOBEC3H transcripts derived from human peripheral blood mononuclear cells are polymorphic in sequence and subject to alternative splicing. We found that APOBEC3H variants encoding a SNP cluster (G105R, K121D and E178D, hapII-RDD) restricted human immunodeficiency virus type 1 (HIV-1) more efficiently than wild-type APOBEC3H (hapI-GKE). All APOBEC3H variants tested were resistant to HIV-1 Vif, the viral protein that efficiently counteracts APOBEC3G/3F activity. Alternative splicing of APOBEC3H was common and resulted in variants with distinct C-terminal regions and variable antiretroviral activities. Splice variants of hapI-GKE displayed a wide range of antiviral activities, whereas similar splicing events in hapII-RDD resulted in proteins that uniformly and efficiently restricted viral infectivity (>20-fold). Site-directed mutagenesis identified G105R in hapI-GKE and D121K in hapII-RDD as critical substitutions leading to an average additional 10-fold increase in antiviral activity. APOBEC3H variants were catalytically active and, similarly to APOBEC3F, favored a GA dinucleotide context. HIV-1 mutagenesis as a mode of action for APOBEC3H is suggested by the decrease of restriction observed with a cytidine deaminase domain mutant and the inverse correlation between G-to-A mutations and infectivity. Thus, the anti-HIV activity of APOBEC3H seems to be regulated by a combination of genomic variation and alternative splicing. Since prevalence of hapII-RDD is high in populations of African descent, these findings raise the possibility that some individuals may harbor effective as well as HIV-1 Vif-resistant intracellular antiviral defense mechanisms.