title: Narrow-host-range IncP plasmid pHH502-1 lacks a complete IncP replication system.
abstract: Plasmid pHH502-1 shows incompatibility only towards members of the IncP group, but has a narrower host range than typical members of that group. In contrast to other IncP plasmids its replication was not affected by a high-copy-number plasmid carrying the replication origin (oriV) of IncP plasmid RK2. Southern blotting of pHH502-1 revealed homology to oriV, consistent with its incompatibility phenotype, but no homology to trfA, the essential replication gene of RK2. Thus it is probable that pHH502-1 does not possess a functional IncP replication system, accounting for its restricted host range. A restriction map of pHH502-1 was constructed and the mercury-resistance determinant was localized to Tn735, which also carries the trimethoprim-resistance determinant and is related to Tn21. The presence of a korB-like function on pHH502-1 was also demonstrated.
authors.affiliation: Department of Genetics, University of Birmingham, UK.
authors.forename: C A
authors.initials: CA
authors.lastname: Smith
authors.forename: C M
authors.initials: CM
authors.lastname: Thomas
mesh_terms: D004251:DNA Transposable Elements; D004269:DNA, Bacterial; D004926:Escherichia coli / Q000235:genetics; D010957:Plasmids; D012689:Sequence Homology, Nucleic Acid
chemical_list: D004251:DNA Transposable Elements; D004269:DNA, Bacterial