"SWI/SNF Chromatin Remodeling Requires Changes in DNA Topology".
Igor Gavin1, Peter J. Horn1, and Craig L. Peterson1
1 Program in Molecular Medicine, Department of Biochemistry and Molecular Biology, University of Massachusetts Medical School, Worcester, Massachusetts 01605
Corresponding author: Craig L. Peterson*, (508) 856-5858 (phone),
(508) 856-4289 (fax),
E-mail: craig.peterson@umassmed.edu
ySWI/SNF complex belongs to a family of enzymes that use the energy
of ATP hydrolysis to remodel chromatin structure. Here we examine the role
of DNA topology in the mechanism of ySWI/SNF remodeling. We find that the
ability of ySWI/SNF to enhance accessibility of nucleosomal DNA is nearly
eliminated when DNA topology is constrained in small circular nucleosomal
arrays and that this inhibition can be alleviated by topoisomerases. Furthermore,
we demonstrate that remodeling of these substrates does not require dramatic
histone octamer movements or displacement. Our results suggest a model
in which ySWI/SNF remodels nucleosomes by using the energy of ATP hydrolysis
to drive local changes in DNA twist.
Additional References:
1. "Generation of Superhelical Torsion by ATP-Dependent Chromatin Remodeling Activities".
2. "Selective Control of DNA Helix Openings During Gene Regulation".