Evolution of the Human Immunodeficiency Virus Type 1 Long Terminal Repeat Promoter by Conversion of an NF-κB Enhancer Element into a GABP Binding Site
Evolution of the Human Immunodeficiency Virus Type 1 Long Terminal Repeat Promoter by Conversion of an NF-κB Enhancer Element into a GABP Binding Site
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通过将 NF-κB 增强子元件转换为 GABP 结合位点来进化人类免疫缺陷病毒 1 型长末端重复启动子
DOI：
10.1128/jvi.73.2.1331-1340.1999
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发表时间：
1999
影响因子：
5.4
通讯作者：
B. Berkhout
中科院分区：
文献类型：
--
作者：
K. Verhoef;R. Sanders;V. Fontaine;S. Kitajima;B. Berkhout
人类免疫缺陷病毒1型（HIV-1）的转录受病毒达特蛋白和细胞因子的调控，其浓度和活性可能取决于细胞类型。因此，优化病毒长末端重复（LTR）启动子序列以适应靶宿主细胞的特定核环境。在Tat缺陷、复制能力差的HIV-1突变体的长期培养中，我们选择了一种复制速度更快的病毒，该病毒在两个高度保守的NF-κB结合位点的上游拷贝中缺失了1个核苷酸。在蛋白结合试验中，变体增强子序列显示NF-κB结合的严重丧失。有趣的是，我们观察到一种新的结合活性，它对NF-κB序列的变异体具有特异性，并且存在于缺乏NF-κB的未受刺激细胞的核提取物中。这些结果表明NF-κB位点的失活与另一种转录因子的结合一致。该因子结合的序列要求的精细映射揭示了与Ets结合位点相似的核心序列，并且用抗体进行的超移位测定证明了GABP转录因子的参与。用LTR-氯霉素乙酰转移酶构建体进行的瞬时转染实验表明，在不存在达特的情况下，变体LTR启动子被GABP特异性抑制，但该启动子比野生型LTR对达特的响应性显著更高。将该GABP位点引入LAI病毒中，在含有很少NF-κB蛋白的SupT 1细胞中产生了特定的适应性增益。这些结果表明，GABP增强Tat介导的激活LTR转录和病毒复制在某些细胞类型。NF-κB转化为GABP结合位点可能也发生在HIV-1的全球传播过程中，因为我们注意到泰国E亚型分离株中存在相同的LTR修饰。这种典型的LTR启动子结构可能为这些病毒提供独特的生物学特性。
ABSTRACT Human immunodeficiency virus type 1 (HIV-1) transcription is regulated by the viral Tat protein and cellular factors, of which the concentration and activity may depend on the cell type. Viral long terminal repeat (LTR) promoter sequences are therefore optimized to suit the specific nuclear environment of the target host cell. In long-term cultures of a Tat-defective, poorly replicating HIV-1 mutant, we selected for a faster-replicating virus with a 1-nucleotide deletion in the upstream copy of two highly conserved NF-κB binding sites. The variant enhancer sequence demonstrated a severe loss of NF-κB binding in protein binding assays. Interestingly, we observed a new binding activity that is specific for the variant NF-κB sequence and is present in the nuclear extract of unstimulated cells that lack NF-κB. These results suggest that inactivation of the NF-κB site coincides with binding of another transcription factor. Fine mapping of the sequence requirements for binding of this factor revealed a core sequence similar to that of Ets binding sites, and supershift assays with antibodies demonstrated the involvement of the GABP transcription factor. Transient transfection experiments with LTR-chloramphenicol acetyltransferase constructs indicated that the variant LTR promoter is specifically inhibited by GABP in the absence of Tat, but this promoter was dramatically more responsive to Tat than the wild-type LTR. Introduction of this GABP site into the LAI virus yielded a specific gain of fitness in SupT1 cells, which contain little NF-κB protein. These results suggest that GABP potentiates Tat-mediated activation of LTR transcription and viral replication in some cell types. Conversion of an NF-κB into a GABP binding site is likely to have occurred also during the worldwide spread of HIV-1, as we noticed the same LTR modification in subtype E isolates from Thailand. This typical LTR promoter configuration may provide these viruses with unique biological properties.
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DOI：
10.1016/s0021-9258(18)31615-6
发表时间：
1994-12
期刊：
The Journal of biological chemistry
影响因子：
--
作者：
Roland;-M.;SchmidSQ;Susanne LiptayQn;Jonathan;-C.;Betts;Gary J. Nabelll
通讯作者：
Roland;-M.;SchmidSQ;Susanne LiptayQn;Jonathan;-C.;Betts;Gary J. Nabelll
影响因子：
5.4
作者：
Montano, MA;Nixon, CP;Essex, M
通讯作者：
Essex, M
马传染性贫血病毒表达的调节。
影响因子：
11
作者：
Maury,W
通讯作者：
Maury,W
病毒与宿主的相互作用以及鼠和人类致癌逆转录病毒的发病机制。
影响因子：
--
作者：
Tsichlis,PN;Lazo,PA
通讯作者：
Lazo,PA