Forum 02/08/2007

“Structure of a RSC-nucleosome complex and implications for chromatin remodeling”

Francisco J. Asturias, Associate Professor – Department of Cell Biology, The Scripps Research Institute, La Jolla, CA

Nucleosomes are repeatedly removed and reassembled in promoter regions, resulting in transient exposure of the DNA that facilitates interaction with the transcription machinery.  RSC is an essential chromatin remodeling complex in yest that, like other members of the SWI/SNF family of remodeling complexes, relieves repression by nucleosomes in vivo, and perturbs nucleosome structure in an ATP-dependent manner in vitro.  An EM structure of a RSC-nucleosome complex shows RSC interacting with the top and bottom surfaces of the nucleosome, but leaving the DNA free to bulge from the sides for remodeling.  All remodeling complexes share the same basic functional properties.  Therefore, the RSC-nucleosome model provides a structural and mechanistic paradigm for the chromatin remodeling process.

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