Dataset Information

The IntXO-PSL Recombination System Is a Key Component of the Second Maintenance System for Bacillus anthracis Plasmid pXO1.

ABSTRACT: We previously identified three noncontiguous regions on Bacillus anthracis plasmid pXO1 that comprise a system for accurate plasmid partitioning and maintenance. However, deletion of these regions did not decrease retention of certain shortened pXO1 plasmids during vegetative growth. Using two genetic tools developed for DNA manipulation in B. anthracis (the Cre-loxP and Flp-FRT systems), we found two other noncontiguous pXO1 regions that together are sufficient for plasmid stability. This second pXO1 maintenance system includes the tubZ and tubR genes, characteristic of a type III partitioning system, and the IntXO recombinase gene (GBAA_RS29165), encoding a tyrosine recombinase, along with its adjacent 37-bp perfect stem-loop (PSL) target. Insertion of either the tubZ and tubR genes or the IntXO-PSL system into an unstable mini-pXO1 plasmid did not restore plasmid stability. The need for the two components of the second pXO1 maintenance system follows from the sequential roles of IntXO-PSL in generating monomeric circular daughter pXO1 molecules (thereby presumably preventing dimer catastrophe) and of TubZ/TubR in partitioning the monomers during cell division. We show that the IntXO recombinase deletes DNA regions located between two PSL sites in a manner similar to the actions of the Cre-loxP and Flp-FRT systems.Tyrosine recombinases catalyze cutting and joining reactions between short specific DNA sequences. Three types of reactions occur: integration and excision of DNA segments, inversion of DNA segments, and separation of monomeric forms from replicating circular DNA molecules. Here we show that the newly discovered site-specific IntXO-PSL recombinase system that contributes to the maintenance of the B. anthracis plasmid pXO1 can be used for genome engineering in a manner similar to that of the Cre-loxP or Flp-FRT system.

SUBMITTER: Pomerantsev AP

PROVIDER: S-EPMC4936106 | biostudies-literature | 2016 Jul

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

The IntXO-PSL Recombination System Is a Key Component of the Second Maintenance System for Bacillus anthracis Plasmid pXO1.

Pomerantsev Andrei P AP Rappole Catherine C Chang Zanetta Z Chahoud Margaret M Leppla Stephen H SH

Journal of bacteriology 20160627 14

<h4>Unlabelled</h4>We previously identified three noncontiguous regions on Bacillus anthracis plasmid pXO1 that comprise a system for accurate plasmid partitioning and maintenance. However, deletion of these regions did not decrease retention of certain shortened pXO1 plasmids during vegetative growth. Using two genetic tools developed for DNA manipulation in B. anthracis (the Cre-loxP and Flp-FRT systems), we found two other noncontiguous pXO1 regions that together are sufficient for plasmid st ...[more]

PMID: 27137503

Similar Datasets

Project description:BackgroundCereulide, a depsipeptide structurally related to valinomycin, is responsible for the emetic type of gastrointestinal disease caused by Bacillus cereus. Recently, it has been shown that this toxin is produced by a nonribosomal peptide synthetase (NRPS), but its exact genetic organization and biochemical synthesis is unknown.ResultsThe complete sequence of the cereulide synthetase (ces) gene cluster, which encodes the enzymatic machinery required for the biosynthesis of cereulide, was dissected. The 24 kb ces gene cluster comprises 7 CDSs and includes, besides the typical NRPS genes like a phosphopantetheinyl transferase and two CDSs encoding enzyme modules for the activation and incorporation of monomers in the growing peptide chain, a CDS encoding a putative hydrolase in the upstream region and an ABC transporter in the downstream part. The enzyme modules responsible for incorporation of the hydroxyl acids showed an unusual structure while the modules responsible for the activation of the amino acids Ala and Val showed the typical domain organization of NRPS. The ces gene locus is flanked by genetic regions with high homology to virulence plasmids of B. cereus, Bacillus thuringiensis and Bacillus anthracis. PFGE and Southern hybridization showed that the ces genes are restricted to emetic B. cereus and indeed located on a 208 kb megaplasmid, which has high similarities to pXO1-like plasmids.ConclusionThe ces gene cluster that is located on a pXO1-like virulence plasmid represents, beside the insecticidal and the anthrax toxins, a third type of B. cereus group toxins encoded on megaplasmids. The ces genes are restricted to emetic toxin producers, but pXO1-like plasmids are also present in emetic-like strains. These data might indicate the presence of an ancient plasmid in B. cereus which has acquired different virulence genes over time. Due to the unusual structure of the hydroxyl acid incorporating enzyme modules of Ces, substantial biochemical efforts will be required to dissect the complete biochemical pathway of cereulide synthesis.

Dataset Information

The IntXO-PSL Recombination System Is a Key Component of the Second Maintenance System for Bacillus anthracis Plasmid pXO1.

Publications

The IntXO-PSL Recombination System Is a Key Component of the Second Maintenance System for Bacillus anthracis Plasmid pXO1.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets