title: NFI and Oct-1 bend the Ad5 origin in the same direction leading to optimal DNA replication.
abstract: Two cellular transcription factors, nuclear factor I (NFI) and octamer binding protein (Oct-1), bind simultaneously to their recognition sequences in the Ad5 origin of replication thereby enhancing initiation. Using scanning force microscopy we have previously shown that NFI induces a 60 degrees bend in the origin DNA. Here we demonstrate that Oct-1 induces a 42 degrees bend in the origin DNA. Simultaneous binding of NFI and Oct-1 induces an 82 degrees collective bend suggesting that both bends are oriented towards each other. In functional replication assays we further demonstrate that this extensive DNA bending leads to a synergistic enhancement of DNA replication. We propose that collective DNA bending induced by NFI and Oct-1 facilitates the optimal assembly of the preinitiation complex and plays an important role in the stimulatory mechanism of NFI and Oct-1 in replication.
authors.affiliation: Department of Physiological Chemistry, University Medical Centre Utrecht and Centre for Biomedical Genetics, Universiteitsweg 100, 3584 CG Utrecht, The Netherlands.
authors.forename: Monika E
authors.initials: ME
authors.lastname: Mysiak
authors.forename: Claire
authors.initials: C
authors.lastname: Wyman
authors.forename: P Elly
authors.initials: PE
authors.lastname: Holthuizen
authors.forename: Peter C
authors.initials: PC
authors.lastname: van der Vliet
mesh_terms: D000256:Adenoviridae / Q000235:genetics*; D001665:Binding Sites; D022762:CCAAT-Enhancer-Binding Proteins / Q000378:metabolism*; D004261:DNA Replication; D004279:DNA, Viral / Q000096:biosynthesis / Q000737:chemistry / Q000648:ultrastructure; D004268:DNA-Binding Proteins / Q000378:metabolism*; D018625:Microscopy, Atomic Force; D051839:NFI Transcription Factors; D009690:Nucleic Acid Conformation; D050811:Octamer Transcription Factor-1; D018741:Replication Origin; D014157:Transcription Factors / Q000378:metabolism*; D014779:Virus Replication
chemical_list: D022762:CCAAT-Enhancer-Binding Proteins; D004279:DNA, Viral; D004268:DNA-Binding Proteins; D051839:NFI Transcription Factors; D050811:Octamer Transcription Factor-1; D014157:Transcription Factors