title: Metabolic Genetic Screens Reveal Multidimensional Regulation of Virulence Gene Expression in Listeria monocytogenes and an Aminopeptidase That Is Critical for PrfA Protein Activation.
abstract: Listeria monocytogenesis an environmental saprophyte and intracellular bacterial pathogen. Upon invading mammalian cells, the bacterium senses abrupt changes in its metabolic environment, which are rapidly transduced to regulation of virulence gene expression. To explore the relationship betweenL. monocytogenesmetabolism and virulence, we monitored virulence gene expression dynamics across a library of genetic mutants grown under two metabolic conditions known to activate the virulent state: charcoal-treated rich medium containing glucose-1-phosphate and minimal defined medium containing limiting concentrations of branched-chain amino acids (BCAAs). We identified over 100 distinct mutants that exhibit aberrant virulence gene expression profiles, the majority of which mapped to nonessential metabolic genes. Mutants displayed enhanced, decreased, and early and late virulence gene expression profiles, as well as persistent levels, demonstrating a high plasticity in virulence gene regulation. Among the mutants, one was noteworthy for its particularly low virulence gene expression level and mapped to an X-prolyl aminopeptidase (PepP). We show that this peptidase plays a role in posttranslational activation of the major virulence regulator, PrfA. Specifically, PepP mediates recruitment of PrfA to the cytoplasmic membrane, a step identified as critical for PrfA protein activation. This study establishes a novel step in the complex mechanism of PrfA activation and further highlights the cross regulation of metabolism and virulence.
authors.affiliation: Department of Molecular Microbiology and Biotechnology, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel.
authors.forename: Sivan
authors.initials: S
authors.lastname: Friedman
authors.affiliation: Department of Molecular Microbiology and Biotechnology, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel.
authors.forename: Marika
authors.initials: M
authors.lastname: Linsky
authors.affiliation: Department of Molecular Microbiology and Biotechnology, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel.
authors.forename: Lior
authors.initials: L
authors.lastname: Lobel
authors.affiliation: Department of Molecular Microbiology and Biotechnology, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel.
authors.forename: Lev
authors.initials: L
authors.lastname: Rabinovich
authors.affiliation: Department of Molecular Microbiology and Biotechnology, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel.
authors.forename: Nadejda
authors.initials: N
authors.lastname: Sigal
authors.affiliation: Department of Molecular Microbiology and Biotechnology, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel anathe@post.tau.ac.il.
authors.forename: Anat A
authors.initials: AA
authors.lastname: Herskovits
mesh_terms: D000626:Aminopeptidases / Q000378:metabolism*; D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics*; D005260:Female; D015964:Gene Expression Regulation, Bacterial; D005958:Glucosephosphates / Q000378:metabolism; D008089:Listeria monocytogenes / Q000235:genetics* / Q000378:metabolism / Q000472:pathogenicity*; D008088:Listeriosis / Q000382:microbiology; D008264:Macrophages / Q000382:microbiology*; D013058:Mass Spectrometry; D051379:Mice; D008810:Mice, Inbred C57BL; D009154:Mutation; D010454:Peptide Termination Factors / Q000235:genetics*; D012329:RNA, Bacterial / Q000235:genetics; D014774:Virulence / Q000235:genetics; D037521:Virulence Factors / Q000235:genetics*
chemical_list: D001426:Bacterial Proteins; D005958:Glucosephosphates; D010454:Peptide Termination Factors; C545356:PrfA protein, Listeria monocytogenes; D012329:RNA, Bacterial; D037521:Virulence Factors; C031590:glucose-1-phosphate; D000626:Aminopeptidases; C022750:X-Pro aminopeptidase
keywords: Listeria monocytogenes; metabolism; virulence