title: Changes in proteome of the Δhfq strain derived from Francisella tularensis LVS correspond with its attenuated phenotype.
abstract: The posttranscriptional regulatory protein Hfq was shown to be an important determinant of the stress resistance and full virulence in the dangerous human pathogen Francisella tularensis. Transcriptomics brought rather limited clues to the precise contribution of Hfq in virulence. To reveal the molecular basis of the attenuation caused by hfq inactivation, we employed iTRAQ in the present study and compared proteomes of the parent and isogenic Δhfq strains. We show that Hfq modulates the level of 76 proteins. Most of them show decreased abundance in the ∆hfq mutant, thereby indicating that Hfq widely acts rather as a positive regulator of Francisella gene expression. Several key Francisella virulence factors including those encoded within the Francisella pathogenicity island were found among the downregulated proteins, which is in a good agreement with the attenuated phenotype of the Δhfq strain. To further validate the iTRAQ exploratory findings, we subsequently performed targeted LC-SRM analysis of selected proteins. This accurate quantification method corroborated the trends found in the iTRAQ data.
authors.affiliation: Faculty of Military Health Sciences, Institute of Molecular Pathology, University of Defense, Hradec Kralove, Czech Republic.
authors.forename: Juraj
authors.initials: J
authors.lastname: Lenco
authors.forename: Vojtech
authors.initials: V
authors.lastname: Tambor
authors.forename: Marek
authors.initials: M
authors.lastname: Link
authors.forename: Jana
authors.initials: J
authors.lastname: Klimentova
authors.forename: Jiri
authors.initials: J
authors.lastname: Dresler
authors.forename: Miroslav
authors.initials: M
authors.lastname: Peterek
authors.forename: Alain
authors.initials: A
authors.lastname: Charbit
authors.forename: Jiri
authors.initials: J
authors.lastname: Stulik
mesh_terms: D005604:Francisella tularensis / Q000235:genetics / Q000378:metabolism / Q000472:pathogenicity*; D017353:Gene Deletion; D035001:Host Factor 1 Protein / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D013058:Mass Spectrometry; D010641:Phenotype; D020543:Proteome / Q000235:genetics / Q000378:metabolism*; D014406:Tularemia / Q000382:microbiology; D037521:Virulence Factors / Q000235:genetics* / Q000378:metabolism
chemical_list: D035001:Host Factor 1 Protein; D020543:Proteome; D037521:Virulence Factors
keywords: Francisella tularensis; Hfq; Mass spectrometry; Microbiology; Virulence