The yeast SWI-SNF complex facilitates binding of a transcriptional activator to nucleosomal sites in vivo
The yeast SWI-SNF complex facilitates binding of a transcriptional activator to nucleosomal sites in vivo
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DOI：
10.1128/mcb.17.8.4811
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发表时间：
1997-08-01
影响因子：
5.3
通讯作者：
Peterson, CL
中科院分区：
文献类型：
--
作者：
Burns, LG;Peterson, CL
酿酒酵母 SWI-SNF 复合物是许多转录激活剂功能所需的 2-MDa 蛋白质组装体。在此，我们描述了 SWI-SNF 复合物在酵母激活剂 GAL4 转录激活中的作用的实验。我们发现，虽然 GAL4 激活剂与无核小体结合位点结合并激活从无核小体结合位点的转录不需要 SWI-SNF 活性，但 GAL4 在体内与低亲和力核小体结合位点结合并在其发挥作用需要该复合物。这种 SWI-SNF 依赖性可以通过 (i) 用更高亲和力的共有 GAL4 结合序列替换低亲和力位点或 (ii) 将低亲和力位点置于无核小体区域来克服。这些结果定义了 SWI-SNF 依赖基因表达的标准，并提供了第一个体内证据，证明 SWI-SNF 复合物可以通过调节上游激活蛋白的 DNA 结合来调节基因表达。
The Saccharomyces cerevisiae SWI-SNF complex is a 2-MDa protein assembly that is required for the function of many transcriptional activators, Here we describe experiments on the role of the SWI-SNF complex in activation of transcription by the yeast activator GAL4. We find that while SWI-SNF activity is not required for the GAL4 activator to bind to and activate transcription from nucleosome-free binding sites, the complex is required for GAL4 to bind to and function at low-affinity, nucleosomal binding sites in vivo. This SWI-SNF dependence can be overcome by (i) replacing the low-affinity sites with higher-affinity, consensus GAL4 binding sequences or (ii) placing the low-affinity sites into a nucleosome-free region. These results define the criteria for the SWI-SNF dependence of gene expression and provide the first in vivo evidence that the SWI-SNF complex can regulate gene expression by modulating the DNA binding of an upstream activator protein.