title: The Legionella pneumophila Incomplete Phosphotransferase System Is Required for Optimal Intracellular Growth and Maximal Expression of PmrA-Regulated Effectors.
abstract: The nitrogen phosphotransferase system (PTSNtr) is a regulatory cascade present in many bacteria, where it controls different functions. This system is usually composed of three basic components: enzyme INtr(EINtr), NPr, and EIIANtr(encoded by theptsP,ptsO, andptsNgenes, respectively). InLegionella pneumophila, as well as in many otherLegionellaspecies, the EIIANtrcomponent is missing. However, we found that deletion mutations in bothptsPandptsOare partially attenuated for intracellular growth. Furthermore, these two PTSNtrcomponents were found to be required for maximal expression of effector-encoding genes regulated by the transcriptional activator PmrA. Genetic analyses which include the construction of single and double deletion mutants and overexpression of wild-type and mutated forms of EINtr, NPr, and PmrA indicated that the PTSNtrcomponents affect the expression of PmrA-regulated genes via PmrA and independently from PmrB and that EINtrand NPr are part of the same cascade and require their conserved histidine residues in order to function. Furthermore, expression of theLegionella micdadeiEIINtrcomponent inL. pneumophilaresulted in a reduction in the levels of expression of PmrA-regulated genes which was completely dependent on theL. pneumophilaPTS components and theL. micdadeiEIINtrconserved histidine residue. Moreover, reconstruction of theL. pneumophilaPTSin vitroindicated that EINtris phosphorylated by phosphoenolpyruvate (PEP) and transfers its phosphate to NPr. Our results demonstrate that theL. pneumophilaincomplete PTSNtris functional and involved in the expression of effector-encoding genes regulated by PmrA.
authors.affiliation: Department of Molecular Microbiology and Biotechnology, George S. Wise Faculty of Life Sciences, Tel-Aviv University, Tel-Aviv, Israel.
authors.forename: Yariv
authors.initials: Y
authors.lastname: Speiser
authors.affiliation: Department of Molecular Microbiology and Biotechnology, George S. Wise Faculty of Life Sciences, Tel-Aviv University, Tel-Aviv, Israel.
authors.forename: Tal
authors.initials: T
authors.lastname: Zusman
authors.affiliation: Department of Molecular Microbiology and Biotechnology, George S. Wise Faculty of Life Sciences, Tel-Aviv University, Tel-Aviv, Israel.
authors.forename: Anna
authors.initials: A
authors.lastname: Pasechnek
authors.affiliation: Department of Molecular Microbiology and Biotechnology, George S. Wise Faculty of Life Sciences, Tel-Aviv University, Tel-Aviv, Israel gils@tauex.tau.ac.il.
authors.forename: Gil
authors.initials: G
authors.lastname: Segal
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics*; D017353:Gene Deletion; D015964:Gene Expression Regulation, Bacterial; D006801:Humans; D016952:Legionella pneumophila / Q000201:enzymology / Q000235:genetics* / Q000472:pathogenicity*; D007877:Legionnaires' Disease / Q000382:microbiology; D008264:Macrophages / Q000382:microbiology; D010731:Phosphoenolpyruvate Sugar Phosphotransferase System / Q000235:genetics*; D010766:Phosphorylation
chemical_list: D001426:Bacterial Proteins; C081902:pmrA protein, Bacteria; D010731:Phosphoenolpyruvate Sugar Phosphotransferase System
keywords: Legionella; PmrA two-component system; effector gene expression; phosphotransferase system (PTS)