title: The segregation of Escherichia coli minichromosomes constructed in vivo by recombineering.
abstract: Circularized regions of the chromosome containing the origin of replication, oriC, can be maintained as autonomous minichromosomes, oriC plasmids. We show that oriC plasmids containing precise, pre-determined segments of the chromosome can be generated by a simple in vivo recombineering technique. We generated two such plasmids carrying fluorescent markers. These were transferred to a recipient strain with a different fluorescent marker near the chromosomal copy of oriC. Thus the fates of the oriC plasmid and chromosomal origins could be followed independently in living cells by fluorescence microscopy. In contrast to a previous report, we show that there is a strong tendency of oriC plasmid copies to accumulate at the cell center as a single or double focus at the plane of cell division. This is not simply due to exclusion from the nucleoid space but rather appears to be a specific recognition and retention of the plasmid by some central-located cell site.
authors.affiliation: Gene Regulation and Chromosome Biology Laboratory, National Cancer Institute, CCR, NCI-Frederick, Frederick, MD 21702-1201, USA.
authors.forename: James A
authors.initials: JA
authors.lastname: Sawitzke
authors.forename: Brenda
authors.initials: B
authors.lastname: Youngren
authors.forename: Lynn C
authors.initials: LC
authors.lastname: Thomason
authors.forename: Teresa
authors.initials: T
authors.lastname: Baker
authors.forename: Manjistha
authors.initials: M
authors.lastname: Sengupta
authors.forename: Donald
authors.initials: D
authors.lastname: Court
authors.forename: Stuart
authors.initials: S
authors.lastname: Austin
mesh_terms: D001692:Biological Transport; D020090:Chromosome Segregation; D002876:Chromosomes, Bacterial; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism; D023061:Gene Order; D016366:Open Reading Frames; D010957:Plasmids / Q000235:genetics* / Q000378:metabolism; D011995:Recombination, Genetic