title: The Chd1 chromatin remodeler can sense both entry and exit sides of the nucleosome.
abstract: Chromatin remodelers are essential for establishing and maintaining the placement of nucleosomes along genomic DNA. Yet how chromatin remodelers recognize and respond to distinct chromatin environments surrounding nucleosomes is poorly understood. Here, we use Lac repressor as a tool to probe how a DNA-bound factor influences action of the Chd1 remodeler. We show that Chd1 preferentially shifts nucleosomes away from Lac repressor, demonstrating that a DNA-bound factor defines a barrier for nucleosome positioning. Rather than an absolute block in sliding, the barrier effect was achieved by altered rates of nucleosome sliding that biased redistribution of nucleosomes away from the bound Lac repressor site. Remarkably, in addition to slower sliding toward the LacO site, the presence of Lac repressor also stimulated sliding in the opposite direction. These experiments therefore demonstrate that Chd1 responds to the presence of a bound protein on both entry and exit sides of the nucleosome. This sensitivity to both sides of the nucleosome allows for a faster and sharper response than would be possible by responding to only the entry side, and we speculate that dual entry/exit sensitivity is also important for regularly spaced nucleosome arrays generated by Chd1 and the related ISWI remodelers.
authors.affiliation: T.C. Jenkins Department of Biophysics, Johns Hopkins University, Baltimore, MD 21218, USA.
authors.forename: Ilana M
authors.initials: IM
authors.lastname: Nodelman
authors.affiliation: Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA.
authors.forename: Kyle C
authors.initials: KC
authors.lastname: Horvath
authors.affiliation: Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA.
authors.forename: Robert F
authors.initials: RF
authors.lastname: Levendosky
authors.affiliation: Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA.
authors.forename: Jessica
authors.initials: J
authors.lastname: Winger
authors.affiliation: T.C. Jenkins Department of Biophysics, Johns Hopkins University, Baltimore, MD 21218, USA.
authors.forename: Ren
authors.initials: R
authors.lastname: Ren
authors.affiliation: T.C. Jenkins Department of Biophysics, Johns Hopkins University, Baltimore, MD 21218, USA.
authors.forename: Ashok
authors.initials: A
authors.lastname: Patel
authors.affiliation: Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853, USA.
authors.forename: Ming
authors.initials: M
authors.lastname: Li
authors.affiliation: Department of Physics, LASSP, Cornell University, Ithaca, NY 14853, USA Howard Hughes Medical Institute, Cornell University, Ithaca, NY 14853, USA.
authors.forename: Michelle D
authors.initials: MD
authors.lastname: Wang
authors.affiliation: T.C. Jenkins Department of Biophysics, Johns Hopkins University, Baltimore, MD 21218, USA.
authors.forename: Elijah
authors.initials: E
authors.lastname: Roberts
authors.affiliation: T.C. Jenkins Department of Biophysics, Johns Hopkins University, Baltimore, MD 21218, USA Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA gdbowman@jhu.edu.
authors.forename: Gregory D
authors.initials: GD
authors.lastname: Bowman
mesh_terms: D000818:Animals; D042002:Chromatin Assembly and Disassembly; D004247:DNA / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000378:metabolism*; D056968:Lac Repressors / Q000378:metabolism; D009707:Nucleosomes / Q000378:metabolism*; D011485:Protein Binding; D000072417:Protein Domains; D012441:Saccharomyces cerevisiae; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry / Q000378:metabolism*; D014982:Xenopus laevis
chemical_list: C489847:CHD1 protein, S cerevisiae; D004268:DNA-Binding Proteins; D056968:Lac Repressors; D009707:Nucleosomes; D029701:Saccharomyces cerevisiae Proteins; D004247:DNA