title: The sequence of the mer operon of pMER327/419 and transposon ends of pMER327/419, 330 and 05.
abstract: Three different, independently isolated mercury-resistance-conferring plasmids, pMER327/419, pMER330 and pMER05, from cultures originating from the river Mersey (UK), contain identical regulatory merR genes and transposon ends. The mer determinant from pMER327/419 contains an additional potential ORF (ORF F) located between merP and merA when compared with the archetypal Tn501. Although these plasmids confer narrow-spectrum resistance (resistance to Hg2+, but not organomercurials) their merR genes encode a potential organomercurial-sensing protein. Transposition of the mer of pMER05 into plasmid RP4 was demonstrated and, as with Tn502 and Tn5053, insertion occurred at a specific region. The sequence of pMER05 is identical at the 'left' and 'right' termini and across merR to Tn5053, which was independently isolated from the chromosome of a Xanthomonas sp. bacteria from the Khaidarkan mercury mine in Kirgizia, former Soviet Union [Kholodii et al., J. Mol. Biol. 230 (1993a) 1103-1107]. The transpositional unit of pMER05 is, like that of Tn5053, bounded by DNA homologous to the imperfect 25-bp inverted repeats (IR) of the In2 integron, which brackets antibiotic-resistance cassettes in Tn21 subgroup transposons. At one end of the transposable element, and internal to the In2-like IR, is a 38-bp IR which closely resembles the IR that bounds Tn21.
authors.affiliation: Department of Genetics and Microbiology, Donnan Laboratories, University of Liverpool, UK.
authors.forename: J
authors.initials: J
authors.lastname: Hobman
authors.forename: G
authors.initials: G
authors.lastname: Kholodii
authors.forename: V
authors.initials: V
authors.lastname: Nikiforov
authors.forename: D A
authors.initials: DA
authors.lastname: Ritchie
authors.forename: P
authors.initials: P
authors.lastname: Strike
authors.forename: O
authors.initials: O
authors.lastname: Yurieva
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics*; D001483:Base Sequence; D004251:DNA Transposable Elements; D004268:DNA-Binding Proteins / Q000235:genetics*; D005798:Genes, Bacterial; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D009876:Operon; D010957:Plasmids
chemical_list: D001426:Bacterial Proteins; D004251:DNA Transposable Elements; D004268:DNA-Binding Proteins; C051124:MerR protein, Bacteria