title: Structural and functional features of cis-acting sequences in the basic replicon of plasmid ColIb-P9.
abstract: We have structurally and functionally analyzed the cis-elements essential for ColIb-P9 plasmid DNA replication. The putative oriV region encompassed a region of 172 base pairs (bp) located 152 bp downstream of the repZ gene. A typical dnaA box found in this region proved nonessential for the DNA replication of ColIb-P9. The ssi signal of ColIb-P9 is a homologue of the G-sites of R1 and R100 plasmids. Deletion of the G-site led to 1.5-fold reduction of the copy number, suggesting that although this G-site is not essential, it is important for efficient ColIb-P9 DNA replication. In addition, the ColIb-P9 replicon is highly and extensively homologous with the P307 (RepFIC) replicon, and highly homologous with the R100 (RepFIIA) replicon around the G-site region. These facts imply a common ancestry from which the plasmids have evolved.
authors.affiliation: Department of Agricultural Chemistry, Kyoto University, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Tanaka
authors.forename: H
authors.initials: H
authors.lastname: Sakai
authors.forename: Y
authors.initials: Y
authors.lastname: Honda
authors.forename: T
authors.initials: T
authors.lastname: Nakamura
authors.forename: A
authors.initials: A
authors.lastname: Higashi
authors.forename: T
authors.initials: T
authors.lastname: Komano
mesh_terms: D001483:Base Sequence; D004261:DNA Replication; D004269:DNA, Bacterial / Q000235:genetics*; D008969:Molecular Sequence Data; D010957:Plasmids; D012045:Regulatory Sequences, Nucleic Acid; D012093:Replicon; D015183:Restriction Mapping; D012689:Sequence Homology, Nucleic Acid; D012764:Shigella sonnei / Q000235:genetics; D013329:Structure-Activity Relationship
chemical_list: D004269:DNA, Bacterial