The Yeast SWI-SNF Complex Facilitates Binding of a Transcriptional Activator to Nucleosomal Sites In Vivo
Open Access
- 1 August 1997
- journal article
- Published by Taylor & Francis in Molecular and Cellular Biology
- Vol. 17 (8), 4811-4819
- https://doi.org/10.1128/mcb.17.8.4811
Abstract
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.Keywords
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