title: Chromosome and low copy plasmid segregation in E. coli: visual evidence for distinct mechanisms.
abstract: We have investigated DNA segregation in E. coli by inserting multiple lac operator sequences into the chromosome near the origin of replication (oriC), in the hisC gene, a terminus marker, and into plasmids P1 and F. Expression of a GFP-LacI fusion protein allowed visualization of lac operator localization. oriC was shown to be specifically localized at or near the cell poles, and when duplicated, one copy moved to the site of new pole formation near the site of cell division. In contrast, P1 and F localized to the cell center and on duplication appeared to move rapidly to the quarter positions in the cell. Our analysis suggests that different active processes are involved in movement and localization of the chromosome and of the two plasmids during segregation.
authors.affiliation: Department of Molecular Biology and Microbiology, Tufts University Health Sciences Campus, Boston, Massachusetts 02111, USA.
authors.forename: G S
authors.initials: GS
authors.lastname: Gordon
authors.forename: D
authors.initials: D
authors.lastname: Sitnikov
authors.forename: C D
authors.initials: CD
authors.lastname: Webb
authors.forename: A
authors.initials: A
authors.lastname: Teleman
authors.forename: A
authors.initials: A
authors.lastname: Straight
authors.forename: R
authors.initials: R
authors.lastname: Losick
authors.forename: A W
authors.initials: AW
authors.lastname: Murray
authors.forename: A
authors.initials: A
authors.lastname: Wright
mesh_terms: D002453:Cell Cycle / Q000502:physiology; D002506:Cephalexin / Q000494:pharmacology; D002511:Cephalosporins / Q000494:pharmacology; D002876:Chromosomes, Bacterial / Q000187:drug effects / Q000502:physiology*; D004269:DNA, Bacterial / Q000235:genetics; D004926:Escherichia coli / Q000187:drug effects / Q000235:genetics*; D018628:Gene Dosage; D018715:Microscopy, Video; D010957:Plasmids / Q000032:analysis / Q000187:drug effects / Q000502:physiology*; D018741:Replication Origin / Q000502:physiology
chemical_list: D002511:Cephalosporins; D004269:DNA, Bacterial; D002506:Cephalexin