title: Poly-dA:dT tracts form an in vivo nucleosomal turnstile.
abstract: Nucleosomes regulate many DNA-dependent processes by controlling the accessibility of DNA, and DNA sequences such as the poly-dA:dT element are known to affect nucleosome binding. We demonstrate that poly-dA:dT tracts form an asymmetric barrier to nucleosome movement in vivo, mediated by ATP-dependent chromatin remodelers. We theorize that nucleosome transit over poly-A elements is more energetically favourable in one direction, leading to an asymmetric arrangement of nucleosomes around these sequences. We demonstrate that different arrangements of poly-A and poly-T tracts result in very different outcomes for nucleosome occupancy in yeast, mouse, and human, and show that yeast takes advantage of this phenomenon in its promoter architecture.
authors.affiliation: Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Carl G
authors.initials: CG
authors.lastname: de Boer
authors.affiliation: Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada; Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Timothy R
authors.initials: TR
authors.lastname: Hughes
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D004247:DNA / Q000235:genetics*; D006801:Humans; D051379:Mice; D009707:Nucleosomes / Q000235:genetics*; D011067:Poly dA-dT / Q000235:genetics*; D011401:Promoter Regions, Genetic; D015003:Yeasts / Q000235:genetics
chemical_list: D009707:Nucleosomes; D011067:Poly dA-dT; D000255:Adenosine Triphosphate; D004247:DNA