POLY(DA-DT), A UBIQUITOUS PROMOTER ELEMENT THAT STIMULATES TRANSCRIPTION VIA ITS INTRINSIC DNA-STRUCTURE
POLY(DA-DT), A UBIQUITOUS PROMOTER ELEMENT THAT STIMULATES TRANSCRIPTION VIA ITS INTRINSIC DNA-STRUCTURE
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DOI：
10.1002/j.1460-2075.1995.tb07255.x
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发表时间：
1995-06-01
期刊：
影响因子：
11.4
通讯作者：
STRUHL, K
中科院分区：
文献类型：
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作者：
IYER, V;STRUHL, K
许多酵母启动子含有影响体外核小体形成的均聚dA：dT序列，并且是体内野生型转录水平所需的。在这里，我们表明，聚（dA：dT）是一种新的启动子元件，其功能取决于其内在的结构，而不是其与序列特异性，DNA结合蛋白的相互作用。首先，poly（dA：dT）以长度依赖性和与细胞内Gcn 4水平负相关的方式刺激Gcn 4激活的转录。第二，Datin是唯一已知的poly（dii：dT）结合蛋白，通过poly（dA：dT）序列作为阻遏物。第三，poly（dG：dC），一种结构上不同的均聚物，也影响核小体，具有与poly（dA：dT）几乎相同的转录特性。三种染色质结构探针，包括体内HinfI核酸内切酶切割，表明poly（dA：dT）增加了生理染色质中Gcn 4结合位点和相邻序列的可及性。这些观察结果表明，凭借其内在的结构，聚（dA：dT）局部影响核小体，并增加与附近序列结合的转录因子的可及性。
Many yeast promoters contain homopolymeric dA:dT sequences that affect nucleosome formation in vitro and are required for wild-type levels of transcription in vivo. Here, we show that poly(dA:dT) is a novel promoter element whose function depends on its intrinsic structure, not its interaction with sequence-specific, DNA-binding proteins. First, poly(dA:dT) stimulates Gcn4-activated transcription in a manner that is length dependent and inversely related to intracellular Gcn4 levels. Second, Datin, the only known poly(dii:dT)-binding protein, behaves as a repressor through poly(dA:dT) sequences. Third, poly(dG:dC), a structurally dissimilar homopolymer that also affects nucleosomes, has transcriptional properties virtually identical to those of poly(dA:dT), Three probes of chromatin structure including HinfI endonuclease cleavage in vivo indicate that poly(dA:dT) increases accessibility of the Gcn4 binding site and adjacent sequences in physiological chromatin. These observations suggest that, by virtue of its intrinsic structure, poly(dA:dT) locally affects nucleosomes and increases the accessibility of transcription factors bound to nearby sequences.