Mobilization Function of the pBHR1 Plasmid, a Derivative of the Broad-Host-Range Plasmid pBBR1
| Autor: | Martine Couturier, Cedric Szpirer, Michel Faelen |
|---|---|
| Rok vydání: | 2001 |
| Předmět: |
DNA
Bacterial Transposable element Molecular Sequence Data Replication Origin Sequence alignment Biology Bordetella bronchiseptica Relaxase Microbiology chemistry.chemical_compound Plasmid Bacterial Proteins Catalytic Domain Bacteroides Amino Acid Sequence Promoter Regions Genetic Molecular Biology Gene Peptide sequence Recombination Genetic Genetics DNA Superhelical Gene Expression Regulation Bacterial Relaxosome Molecular biology chemistry Conjugation Genetic DNA Transposable Elements Mutagenesis Site-Directed Plasmids and Transposons DNA Plasmids |
| Zdroj: | Journal of Bacteriology. 183:2101-2110 |
| ISSN: | 1098-5530 0021-9193 |
| DOI: | 10.1128/jb.183.6.2101-2110.2001 |
| Popis: | The pBHR1 plasmid is a derivative of the small (2.6-kb), mobilizable broad-host-range plasmid pBBR1, which was isolated from the gram-negative bacterium Bordetella bronchiseptica (R. Antoine and C. Locht, Mol. Microbiol. 6:1785–1799, 1992). Plasmid pBBR1 consists of two functional cassettes and presents sequence similarities with the transfer origins of several plasmids and mobilizable transposons from gram-positive bacteria. We show that the Mob protein specifically recognizes a 52-bp sequence which contains, in addition to the transfer origin, the promoter of the mob gene. We demonstrate that this gene is autoregulated. The binding of the Mob protein to the 52-bp sequence could thus allow the formation of a protein-DNA complex with a double function: relaxosome formation and mob gene regulation. We show that the Mob protein is a relaxase, and we located the nic site position in vitro. After sequence alignment, the position of the nic site of pBBR1 corresponds with those of the nick sites of the Bacteroides mobilizable transposon Tn 4555 and the streptococcal plasmid pMV158. The oriT of the latter is characteristic of a family of mobilizable plasmids that are found in gram-positive bacteria and that replicate by the rolling-circle mechanism. Plasmid pBBR1 thus appears to be a new member of this group, even though it resides in gram-negative bacteria and does not replicate via a rolling-circle mechanism. In addition, we identified two amino acids of the Mob protein necessary for its activity, and we discuss their involvement in the mobilization mechanism. |
| Databáze: | OpenAIRE |
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