The replication and stable-inheritance functions of IncP-9 plasmid pM3.
Little is known of the transfer and maintenance machinery of the IncP-9 plasmids, which are found in Pseudomonas spp. and include both degradative and resistance plasmids. One such plasmid, pM3, which confers resistance to streptomycin and tetracycline, was found repeatedly in Pseudomonas species from numerous locations in Belarus. pM3 has a broad host range, but is unable to replicate in enterobacteria at 37 degrees C and above. A mini derivative, pMT2, was constructed by partial PstI digestion and ligation with a fragment encoding Km(R). The complete sequence of pMT2 was determined. Analysis of its 8526 bp of pM3 DNA revealed several ORFs whose predicted polypeptide products were found to have similarity to previously analysed proteins involved in plasmid replication (rep gene), transfer (mpf; mating-pair formation gene) and stable maintenance (par, mrs genes). The organization of these genes showed similarity to several plasmid systems including the Ti and pSYM plasmids as well as IncP-1 plasmids. Subcloning narrowed down the region required for replication, and identified the putative rep gene and putative par promoter region as able to express incompatibility. rep deletion mutants were lost from the cell line, and expression of the rep gene was shown to be controlled by negative autoregulation. A pMT2 derivative with an insertion between the rep and par genes showed very weak, if any, ability to replicate autonomously, suggesting that plasmid maintenance may depend on a close interaction of rep and par functions.
Greated
Alicia
A
School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK1.
Titok
Marina
M
Faculty of Biology, Department of Microbiology, Belarus State University, Scorina Av. 4, Minsk 220080, Belarus2.
Krasowiak
Renata
R
School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK1.
Fairclough
Rebecca J
RJ
School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK1.
Thomas
Christopher M
CM
School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK1.
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics*; D004265:DNA Helicases / Q000235:genetics / Q000378:metabolism; D004261:DNA Replication; D004268:DNA-Binding Proteins; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D011549:Pseudomonas / Q000187:drug effects / Q000235:genetics*; D011815:R Factors / Q000235:genetics* / Q000378:metabolism*; D045522:Recombinases; D012093:Replicon; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism; D017422:Sequence Analysis, DNA; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism; D019895:Transposases / Q000235:genetics / Q000378:metabolism
D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; C090051:KorA protein, bacteria; D045522:Recombinases; D012097:Repressor Proteins; D015534:Trans-Activators; C415783:pMT2 protein, bacteria; C045264:replication initiator protein; D019895:Transposases; D004265:DNA Helicases