SWI/SNF chromatin remodeling requires changes in DNA topology.
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.
Gavin
I
I
Program in Molecular Medicine, Department of Biochemistry and Molecular Biology, University of Massachusetts Medical School, Worcester, MA 01605, USA.
Horn
P J
PJ
Peterson
C L
CL
D000818:Animals; D002843:Chromatin / Q000235:genetics* / Q000378:metabolism; D004261:DNA Replication / Q000502:physiology*; D004264:DNA Topoisomerases, Type I / Q000378:metabolism; D004270:DNA, Circular / Q000737:chemistry / Q000235:genetics; D029721:Drosophila Proteins; D004447:Echinodermata; D006657:Histones / Q000235:genetics / Q000378:metabolism; D009690:Nucleic Acid Conformation; D009707:Nucleosomes / Q000235:genetics / Q000378:metabolism; D016601:RNA-Binding Proteins; D017412:Ribonucleoprotein, U1 Small Nuclear / Q000235:genetics* / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism
D002843:Chromatin; D004270:DNA, Circular; D029721:Drosophila Proteins; D006657:Histones; D009707:Nucleosomes; D016601:RNA-Binding Proteins; D017412:Ribonucleoprotein, U1 Small Nuclear; D014157:Transcription Factors; C089969:snf protein, Drosophila; D004264:DNA Topoisomerases, Type I