Wild-type and transactivation-defective mutants of human immunodeficiency virus type 1 Tat protein bind human TATA-binding protein in vitro.
Wild-type and transactivation-defective mutants of human immunodeficiency virus type 1 Tat protein bind human TATA-binding protein in vitro.
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人类免疫缺陷病毒 1 型 Tat 蛋白的野生型和反式激活缺陷突变体在体外与人 TATA 结合蛋白结合。
DOI：
10.1097/00042560-199606010-00005
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发表时间：
1996
期刊：
影响因子：
--
通讯作者：
Morris,CB
中科院分区：
文献类型：
--
作者：
Wang,Z;Morris,GF;Rice,AP;Xiong,W;Morris,CB
达特通过增加转录起始速率和转录延伸效率来调节人类免疫缺陷病毒1型（HIV-1）基因表达。达特促进HIV-1转录前起始复合物形成的能力表明，达特可能靶向基础转录机制的组成部分。以前的研究已经证明，达特直接与人TATA结合蛋白（TBP）和特定的TBP相关因子（TAF），包括TFIID复合物的相互作用。在这里，在体外谷胱甘肽S-转移酶蛋白结合测定含有完全功能或反式激活缺陷的突变体达特蛋白已被用来调查之间的直接相互作用达特和TBP相对于达特反式激活的功能意义。结果表明，全长达特，以及单独的达特的活化结构域，在体外结合人TBP。在体内消除达特反式激活的达特激活结构域内的定点突变（C22 G和P181 S）不能抑制Tat-TBP结合。全长达特、达特单独的激活结构域和缺少N-末端氨基酸残基2-36的达特反式激活缺陷突变体以相同的效率与TBP结合，前提是定位于TBP高度保守羧基末端内氨基酸167-220的H1 α螺旋结构域得以维持。这些数据表明，达特的激活结构域内映射的活动，这是从Tat-TBP结合不同，是需要由达特的反式激活。
Tat regulates human immunodeficiency virus type 1 (HIV-1) gene expression by increasing both the rate of transcription initiation and the efficiency of transcription elongation. The ability of Tat to facilitate HIV-1 transcription preinitiation complex formation suggests that components of the basal transcriptional machinery may be targeted by Tat. Previous studies have demonstrated that Tat interacts directly with the human TATA-binding protein (TBP) and specific TBP-associated factors (TAFs) that comprise the TFIID complex. Here, in vitro glutathione S-transferase protein binding assays containing fully functional or transactivation-defective mutant Tat proteins have been used to investigate the functional significance of the direct interaction between Tat and TBP relative to Tat transactivation. Results demonstrate that full-length Tat, as well as the activation domain of Tat alone, binds human TBP in vitro. Site-directed mutations within the activation domain of Tat (C22G and P181S) that abrogate transactivation by Tat in vivo fail to inhibit Tat-TBP binding. Full-length Tat, the activation domain of Tat alone, and a transactivation-defective mutant of Tat that lacks N-terminal amino acid residues 2-36 bind with equal efficiencies to TBP provided that the H1 α helical domain that maps to amino acids 167-220 within the highly conserved carboxyl terminus of TBP is maintained. These data indicate that an activity mapped within the activation domain of Tat, which is distinct from Tat-TBP binding, is required for transactivation by Tat.