title: Influence of different functional elements of plasmid pGT232 on maintenance of recombinant plasmids in Lactobacillus reuteri populations in vitro and in vivo.
abstract: Plasmid pGT232 (5.1 kb), an indigenous plasmid of Lactobacillus reuteri 100-23, was determined, on the basis of nucleotide and deduced protein sequence data, to belong to the pC194-pUB110 family of plasmids that replicate via the rolling-circle mechanism. The minimal replicon of pGT232 was located on a 1.7-kb sequence consisting of a double-strand origin of replication and a gene encoding the replication initiation protein, repA. An erythromycin-selectable recombinant plasmid containing this minimal replicon was stably maintained (>97% erythromycin-resistant cells) without antibiotic selection in an L. reuteri population under laboratory growth conditions but was poorly maintained (<33% resistant cells) in the L. reuteri population inhabiting the murine gastrointestinal tract. Stable maintenance (>90% resistant cells) of pGT232-derived plasmids in the lactobacillus population in vivo required an additional 1.0-kb sequence which contained a putative single-strand replication origin (SSO). The SSO of pGT232 is believed to be novel and functions in an orientation-specific manner.
authors.affiliation: Department of Microbiology, University of Otago, Dunedin, New Zealand.
authors.forename: N C
authors.initials: NC
authors.lastname: Heng
authors.forename: J M
authors.initials: JM
authors.lastname: Bateup
authors.forename: D M
authors.initials: DM
authors.lastname: Loach
authors.forename: X
authors.initials: X
authors.lastname: Wu
authors.forename: H F
authors.initials: HF
authors.lastname: Jenkinson
authors.forename: M
authors.initials: M
authors.lastname: Morrison
authors.forename: G W
authors.initials: GW
authors.lastname: Tannock
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D004261:DNA Replication; D007778:Lactobacillus / Q000235:genetics*; D008969:Molecular Sequence Data; D010957:Plasmids; D011995:Recombination, Genetic; D012093:Replicon / Q000235:genetics*; D015183:Restriction Mapping; D017384:Sequence Deletion