Preferential accessibility of the yeast his3 promoter is determined by a general property of the DNA sequence, not by specific elements
Preferential accessibility of the yeast his3 promoter is determined by a general property of the DNA sequence, not by specific elements
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DOI：
10.1128/mcb.20.18.6668-6676.2000
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发表时间：
2000-09-01
影响因子：
5.3
通讯作者：
Struhl, K
中科院分区：
文献类型：
--
作者：
Mai, X;Chou, S;Struhl, K
酵母启动子区通常比非启动子区更容易接近核蛋白。如在活的酵母细胞中通过HinfI内切酶切割所测定的，位于所有7个测试基因的启动子中的HinfI位点比邻近的非启动子区域中的位点更易接近5至20倍。his 3启动子区域内的HinfI超敏性是局部确定的，因为当该区域a-as易位到ade 2结构基因的中间时观察到。对his 3启动子的详细分析表明，优先可及性不是由特定元件如Gcn 4结合位点、聚（dA-dT）序列、TATA元件或起始元件或转录活性决定的。然而，在任一方向的启动子区域的逐步删除导致HinfI可及性的逐步丧失。优先可及性独立于Swi-Snf染色质重塑复合物、Gcn 5组蛋白乙酰化酶复合物Ada和佐贺以及Rad 6，其泛素化组蛋白H2 B。这些结果表明，his 3（以及可能的其他）启动子区域的优先可及性由DNA序列的一般性质决定（例如，碱基组成或相关特征），而不是通过定义的序列元件。紧凑的酵母基因组组织成固有的不同的启动子和非启动子区域可以确保转录因子优先结合到启动子中的适当位点，而不是非启动子区域中多余的无关但同样高亲和力的位点。
Yeast promoter regions are often more accessible to nuclear proteins than are nonpromoter regions. As assayed by HinfI endonuclease cleavage in living yeast cells, HinfI sites located in the promoters of all seven genes tested were 5- to 20-fold more accessible than sites in adjacent nonpromoter regions. HinfI hypersensitivity within the his3 promoter region is locally determined, since it was observed when this region a-as translocated to the middle of the ade2 structural gene. Detailed analysis of the his3 promoter indicated that preferential accessibility is not determined by specific elements such as the Gcn4 binding site, poly(dA-dT) sequences, TATA elements, or initiator elements or by transcriptional activity. However, progressive deletion of the promoter region in either direction resulted in a progressive loss of HinfI accessibility. Preferential accessibility is independent of the Swi-Snf chromatin remodeling complex, Gcn5 histone acetylase complexes Ada and SAGA and Rad6, which ubiquitinates histone H2B. These results suggest that preferential accessibility of the his3 (and presumably other) promoter regions is determined by a general property of the DNA sequence (e.g., base composition or a related feature) rather than by defined sequence elements. The organization of the compact yeast genome into inherently distinct promoter and nonpromoter regions may ensure that transcription factors bind preferentially to appropriate sites in promoters rather than to the excess of irrelevant but equally high-affinity sites in nonpromoter regions.