title: Functional Characterization of Pseudomonas Contact Dependent Growth Inhibition (CDI) Systems.
abstract: Contact-dependent inhibition (CDI) toxins, delivered into the cytoplasm of target bacterial cells, confer to host strain a significant competitive advantage. Upon cell contact, the toxic C-terminal region of surface-exposed CdiA protein (CdiA-CT) inhibits the growth of CDI- bacteria. CDI+ cells express a specific immunity protein, CdiI, which protects from autoinhibition by blocking the activity of cognate CdiA-CT. CdiA-CT are separated from the rest of the protein by conserved peptide motifs falling into two distinct classes, the "E. coli"- and "Burkholderia-type". CDI systems have been described in numerous species except in Pseudomonadaceae. In this study, we identified functional toxin/immunity genes linked to CDI systems in the Pseudomonas genus, which extend beyond the conventional CDI classes by the variability of the peptide motif that delimits the polymorphic CdiA-CT domain. Using P. aeruginosa PAO1 as a model, we identified the translational repressor RsmA as a negative regulator of CDI systems. Our data further suggest that under conditions of expression, P. aeruginosa CDI systems are implicated in adhesion and biofilm formation and provide an advantage in competition assays. All together our data imply that CDI systems could play an important role in niche adaptation of Pseudomonadaceae.
authors.affiliation: Laboratoire d'Ingénierie des Systèmes Macromoléculaires, CNRS UMR7255, Université Aix Marseille, Marseille, France.|Bases Moléculaires et Structurales des Systèmes Infectieux, CNRS UMR 5086, Université Lyon 1, Institut de Biologie et Chimie des Protéines, Lyon, France.
authors.forename: Chryslène
authors.initials: C
authors.lastname: Mercy
authors.affiliation: Laboratoire d'Ingénierie des Systèmes Macromoléculaires, CNRS UMR7255, Université Aix Marseille, Marseille, France.
authors.forename: Bérengère
authors.initials: B
authors.lastname: Ize
authors.affiliation: Bases Moléculaires et Structurales des Systèmes Infectieux, CNRS UMR 5086, Université Lyon 1, Institut de Biologie et Chimie des Protéines, Lyon, France.
authors.forename: Suzana P
authors.initials: SP
authors.lastname: Salcedo
authors.affiliation: Laboratoire d'Ingénierie des Systèmes Macromoléculaires, CNRS UMR7255, Université Aix Marseille, Marseille, France.
authors.forename: Sophie
authors.initials: S
authors.lastname: de Bentzmann
authors.affiliation: Laboratoire d'Ingénierie des Systèmes Macromoléculaires, CNRS UMR7255, Université Aix Marseille, Marseille, France.|Bases Moléculaires et Structurales des Systèmes Infectieux, CNRS UMR 5086, Université Lyon 1, Institut de Biologie et Chimie des Protéines, Lyon, France.
authors.forename: Sarah
authors.initials: S
authors.lastname: Bigot
mesh_terms: D001422:Bacterial Adhesion / Q000235:genetics / Q000502:physiology; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D018441:Biofilms / Q000254:growth & development; D004926:Escherichia coli / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D011549:Pseudomonas / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism*; D060888:Real-Time Polymerase Chain Reaction
chemical_list: D001426:Bacterial Proteins