title: 5-Bromouracil disrupts nucleosome positioning by inducing A-form-like DNA conformation in yeast cells.
abstract: 5-Bromodeoxyuridine (BrdU) modulates expression of particular genes associated with cellular differentiation and senescence. Our previous studies have suggested an involvement of chromatin structure in this phenomenon. Here, we examined the effect of 5-bromouracil on nucleosome positioning in vivo using TALS plasmid in yeast cells. This plasmid can stably and precisely be assembled nucleosomes aided by the alpha2 repressor complex bound to its alpha2 operator. Insertion of AT-rich sequences into a site near the operator destabilized nucleosome positioning dependent on their length and sequences. Addition of BrdU almost completely disrupted nucleosome positioning through specific AT-tracts. The effective AT-rich sequences migrated faster on polyacrylamide gel electrophoresis, and their mobility was further accelerated by substitution of thymine with 5-bromouracil. Since this property is indicative of a rigid conformation of DNA, our results suggest that 5-bromouracil disrupts nucleosome positioning by inducing A-form-like DNA.
authors.affiliation: International Graduate School of Arts and Sciences, Yokohama City University, Seto 22-2, Kanazawa-Ku, Yokohama, Kanagawa 236-0027, Japan.
authors.forename: Kensuke
authors.initials: K
authors.lastname: Miki
authors.forename: Mitsuhiro
authors.initials: M
authors.lastname: Shimizu
authors.forename: Michihiko
authors.initials: M
authors.lastname: Fujii
authors.forename: Mohammad Nazir
authors.initials: MN
authors.lastname: Hossain
authors.forename: Dai
authors.initials: D
authors.lastname: Ayusawa
mesh_terms: D001976:Bromouracil / Q000008:administration & dosage*; D045584:Chromosome Positioning / Q000187:drug effects / Q000235:genetics*; D044704:DNA, A-Form / Q000737:chemistry* / Q000235:genetics*; D004305:Dose-Response Relationship, Drug; D009690:Nucleic Acid Conformation / Q000187:drug effects; D009707:Nucleosomes / Q000187:drug effects / Q000235:genetics*; D012441:Saccharomyces cerevisiae / Q000187:drug effects* / Q000235:genetics*
chemical_list: D044704:DNA, A-Form; D009707:Nucleosomes; D001976:Bromouracil