title: Two separate DNA sequences within oriC participate in accurate chromosome segregation in Bacillus subtilis.
abstract: Current views of bacterial chromosome segregation vary in respect of the likely presence or absence of an active segregation mechanism involving a mitotic-like apparatus. Furthermore, little is known about cis-acting elements for chromosome segregation in bacteria. In this report, we show that two separate DNA regions, a 3' coding region of dnaA and the AT-rich sequence between dnaA and dnaN (the initial opening site of duplex DNA during replication), are necessary for efficient segregation of the chromosome in Bacillus subtilis. When a plasmid replicon was integrated into argG, far from oriC, on the chromosome and then the oriC function was disrupted, the oriC-deleted mutant formed anucleate cells at 5% possibly because of defects in chromosome segregation. However, when the two DNA sequences were added near oriN, frequency of anucleate cells decreased to 1%. In these cells, the origin (argG) regions were localized near cell poles, whereas they were randomly distributed in cells without the two DNA sequences. These results suggest that the two DNA sequences in and downstream of the dnaA gene participate in correct positioning of the replication origin region within the cell and that this function is associated with accurate chromosome segregation in B. subtilis.
authors.affiliation: Graduate School of Biological Sciences, nara Institue of Science and Technology, Takayama, Ikoma, Nara, Japan.
authors.forename: Ryosuke
authors.initials: R
authors.lastname: Kadoya
authors.forename: Anwarul K M
authors.initials: AK
authors.lastname: Hassan
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Kasahara
authors.forename: Naotake
authors.initials: N
authors.lastname: Ogasawara
authors.forename: Shigeki
authors.initials: S
authors.lastname: Moriya
mesh_terms: D001412:Bacillus subtilis / Q000235:genetics* / Q000254:growth & development; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D001483:Base Sequence; D020090:Chromosome Segregation; D002876:Chromosomes, Bacterial / Q000235:genetics / Q000502:physiology*; D004268:DNA-Binding Proteins / Q000737:chemistry* / Q000235:genetics; D004259:DNA-Directed DNA Polymerase; D004742:Enhancer Elements, Genetic / Q000235:genetics*; D005434:Flow Cytometry; D017353:Gene Deletion; D017404:In Situ Hybridization, Fluorescence; D008856:Microscopy, Fluorescence; D009876:Operon; D051738:Origin Recognition Complex; D012808:Sigma Factor; D014157:Transcription Factors; D014764:Viral Proteins / Q000737:chemistry* / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; C066312:DnaA protein, Bacteria; C114650:OriC chromosomal replication origin; D051738:Origin Recognition Complex; D012808:Sigma Factor; D014157:Transcription Factors; D014764:Viral Proteins; C092468:spoIIR protein, Bacillus subtilis; C030069:spore-specific proteins, Bacillus; D004259:DNA-Directed DNA Polymerase; C083980:dnaN protein, Bacteria