title: Plasmid host-range: restrictions to F replication in Pseudomonas.
abstract: Host-range, a fundamental property of a bacterial plasmid, is primarily determined by the plasmid replication system. To investigate the basis of the restricted host-range of the well-studied F-plasmid of Escherichia coli, we characterized in vitro the interactions of the host DnaA initiation protein and DnaB helicase from Pseudomonas aeruginosa and Pseudomonas putida with the replication origin, oriS, and initiation protein, RepE, of the RepFIA replicon. The results presented here show that a pre-priming complex can form at the F-origin with the replication proteins from the non-native hosts in the presence of RepE. However, RepE cannot form a stable complex with DnaB of P. aeruginosa or P. putida but does stably interact with E. coli DnaB. This unstable association may affect the ability of F to replicate in Pseudomonas. In addition, replication studies in vivo suggest that inefficient expression of the RepE initiation protein from its native promoter in Pseudomonas is a factor in restricting its host-range. This, however, is not the only barrier to F replication, as mini-F derivatives with an alternative promoter for RepE expression do not replicate in P. putida and are not stably maintained in P. aeruginosa.
authors.affiliation: Division of Biological Sciences and Center for Molecular Genetics, University of California San Diego, La Jolla, CA 92093-0322, USA.
authors.forename: Zhenping
authors.initials: Z
authors.lastname: Zhong
authors.forename: Donald
authors.initials: D
authors.lastname: Helinski
authors.forename: Aresa
authors.initials: A
authors.lastname: Toukdarian
mesh_terms: D000251:Adenosine Triphosphatases / Q000235:genetics / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D004265:DNA Helicases / Q000235:genetics / Q000378:metabolism; D004261:DNA Replication / Q000235:genetics*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D053488:DnaB Helicases; D004926:Escherichia coli / Q000235:genetics; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism; D005144:F Factor / Q000235:genetics / Q000502:physiology*; D011401:Promoter Regions, Genetic; D011549:Pseudomonas / Q000235:genetics*; D018741:Replication Origin / Q000235:genetics; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism; D013045:Species Specificity
chemical_list: D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; C066312:DnaA protein, Bacteria; D029968:Escherichia coli Proteins; C074164:RepE protein, E coli; D012097:Repressor Proteins; D000251:Adenosine Triphosphatases; C506730:dnaB protein, E coli; D004265:DNA Helicases; D053488:DnaB Helicases