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DNA-binding properties of the yeast SWI/SNF complex
J Quinn1, A M Fyrberg, R W Ganster
1Program in Molecular Medicine and Department of Biochemistry and Molecular Biology, University of Massachusetts Medical Centre, Worcester, 01605, USA.
Nature
|February 29, 1996
Summary
The SWI/SNF complex, crucial for yeast transcription, directly binds DNA. This finding challenges previous beliefs and highlights its role in chromatin remodeling.
Area of Science:
- Molecular Biology
- Yeast Genetics
- Chromatin Biology
Background:
- The SWI/SNF complex is essential for transcriptional activation in yeast.
- It is understood to counteract chromatin-mediated repression.
- Previous studies suggested SWI/SNF does not bind DNA due to lack of motifs and activity in extracts.
Purpose of the Study:
- To investigate the DNA-binding properties of the SWI/SNF complex.
- To determine if SWI/SNF directly interacts with DNA.
- To elucidate the mechanism by which SWI/SNF influences chromatin structure.
Main Methods:
- Biochemical assays to assess DNA binding affinity.
- Analysis of DNA-protein interactions, including minor groove binding.
- Electrophoretic techniques to study supercoiling of plasmid DNA.
Main Results:
- The SWI/SNF complex exhibits high affinity for DNA.
- Its DNA-binding characteristics resemble those of HMG-box proteins.
- The complex binds the minor groove of DNA, interacts with four-way junction DNA, and induces positive supercoils.
Conclusions:
- The SWI/SNF complex possesses intrinsic DNA-binding capabilities.
- These DNA-binding properties are likely integral to its function in chromatin remodeling.
- This study reframes the understanding of SWI/SNF's role in transcriptional regulation.