title: Left-handedly curved DNA regulates accessibility to cis-DNA elements in chromatin.
abstract: There is little information on chromatin structure that allows access of trans-acting transcription factors. Logically, the target DNA elements become accessible by either exposing themselves towards the environment on the surface of the nucleosome, or making the regulatory region free of the nucleosome. Here, we demonstrate that curved DNA that mimics a negative supercoil can play both roles in the promoter region. By constructing 35 reporter plasmids and using in vivo assay systems, we scrutinized the relationships between upstream DNA geometry, nucleosome positioning and promoter activity. When the left-handedly curved DNA was linked to the herpes simplex virus thymidine kinase (HSV tk) promoter at a specific rotational phase and distance, the curved DNA attracted the nucleosome and the TATA box was thereby left in the linker DNA with its minor groove facing outwards, which led to the activation of transcription. Neither planar curving, nor right-handedly curved DNA nor straight DNA had this effect. Our results seem to provide a clue for solving the problem of why curved DNA is often located near transcriptional control regions.
authors: Department of Biology, Faculty of Science and Engineering, Konan University, 8-9-1 Okamoto, Higashinada-ku, Kobe 658-8501, Japan.
authors: Jun-ichi
authors: J
authors: Nishikawa
authors: Miho
authors: M
authors: Amano
authors: Yoshiro
authors: Y
authors: Fukue
authors: Shigeo
authors: S
authors: Tanaka
authors: Haruka
authors: H
authors: Kishi
authors: Yoshiko
authors: Y
authors: Hirota
authors: Kinya
authors: K
authors: Yoda
authors: Takashi
authors: T
authors: Ohyama
mesh_terms: D000818:Animals; D001483:Base Sequence; D019556:COS Cells; D002522:Chlorocebus aethiops; D002843:Chromatin / Q000235:genetics*; D004247:DNA / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D018983:DNA Footprinting / Q000379:methods; D005786:Gene Expression Regulation; D008156:Luciferases / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D009707:Nucleosomes / Q000235:genetics / Q000378:metabolism; D010957:Plasmids / Q000737:chemistry / Q000235:genetics; D011401:Promoter Regions, Genetic / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D020218:Response Elements / Q000235:genetics*; D016385:TATA Box / Q000235:genetics; D013937:Thymidine Kinase / Q000235:genetics; D014158:Transcription, Genetic / Q000235:genetics
chemical_list: D002843:Chromatin; D009707:Nucleosomes; D011993:Recombinant Fusion Proteins; D004247:DNA; D008156:Luciferases; D013937:Thymidine Kinase