title: The curved DNA structure in the 5'-upstream region of the light-responsive genes: its universality, binding factor and function for cyanobacterial psbA transcription.
abstract: A unique DNA curvature, the CIT, has been found in the 5'-upstream region of the psbA2 gene, which exhibits basal, light-responsive and circadian rhythmic transcription, in a unicellular photosynthetic cyanobacterium, Microcystis aeruginosa K-81. In this study, we report the universality of curvatures found in 5'-upstream regions in the psbA family and the function of the curvature in gene expression. Intrinsic curvatures were identified within 1000 bp upstream from the psbA genes in another cyanobacterium, a red alga and in plants (monocot and dicot). Mutagenized curvatures were constructed and confirmed to have disrupted architecture by gel electrophoresis and atomic force microscopy. Relatively small amounts but light-responsive transcripts of psbA2 were observed in cyanobacterial transformants harboring the mutagenized curvature under light/dark and light/high-light conditions. This shows that the curvature is important for basal transcription. In vitro primer extension and DNA mobility shift assay revealed that factors which might bind to the region upstream from the bending center contribute to the effective basal transcription of psbA2.
authors.affiliation: Laboratory of Molecular Genetics, School of Agriculture, Ibaraki University, Ami 3-21-1, Inashiki-gun, Ibaraki 300-0332, Japan.
authors.forename: Munehiko
authors.initials: M
authors.lastname: Asayama
authors.forename: Hideki
authors.initials: H
authors.lastname: Kato
authors.forename: Junko
authors.initials: J
authors.lastname: Shibato
authors.forename: Makoto
authors.initials: M
authors.lastname: Shirai
authors.forename: Takashi
authors.initials: T
authors.lastname: Ohyama
mesh_terms: D024506:5' Flanking Region / Q000235:genetics*; D001483:Base Sequence; D000458:Cyanobacteria / Q000235:genetics*; D004247:DNA / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism*; D024202:Electrophoretic Mobility Shift Assay; D015964:Gene Expression Regulation, Bacterial / Q000528:radiation effects; D005798:Genes, Bacterial / Q000235:genetics; D008027:Light; D018625:Microscopy, Atomic Force; D008969:Molecular Sequence Data; D016296:Mutagenesis; D009690:Nucleic Acid Conformation; D010788:Photosynthesis / Q000235:genetics; D045322:Photosynthetic Reaction Center Complex Proteins / Q000235:genetics*; D045332:Photosystem II Protein Complex; D011485:Protein Binding; D012329:RNA, Bacterial / Q000096:biosynthesis / Q000235:genetics; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D014158:Transcription, Genetic / Q000235:genetics / Q000528:radiation effects*
chemical_list: D004268:DNA-Binding Proteins; D045322:Photosynthetic Reaction Center Complex Proteins; D045332:Photosystem II Protein Complex; D012329:RNA, Bacterial; D012333:RNA, Messenger; C422369:photosystem II, psbA subunit; D004247:DNA