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Attenuating Listeria monocytogenes virulence by targeting the regulatory protein PrfA
Umeå University, Faculty of Science and Technology, Department of Chemistry. Umeå University, Faculty of Medicine, Umeå Centre for Microbial Research (UCMR).
Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine). Umeå University, Faculty of Medicine, Umeå Centre for Microbial Research (UCMR). Umeå University, Faculty of Medicine, Molecular Infection Medicine Sweden (MIMS).
Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine). Umeå University, Faculty of Medicine, Molecular Infection Medicine Sweden (MIMS). Umeå University, Faculty of Medicine, Umeå Centre for Microbial Research (UCMR).
Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine). Umeå University, Faculty of Medicine, Umeå Centre for Microbial Research (UCMR). Umeå University, Faculty of Medicine, Molecular Infection Medicine Sweden (MIMS).
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(English)Manuscript (preprint) (Other academic)
Abstract [en]

The transcriptional activator PrfA, a member of the Crp/Fnr family, controls the expression of some key virulence factors necessary for infection by the human bacterial pathogen Listeria monocytogenes. Phenotypic screening identified ring-fused 2-pyridone molecules that at low micromolar concentrations attenuate L. monocytogenes infectivity by reducing the expression of virulence genes, without compromising bacterial growth. These inhibitors bind the transcriptional regulator PrfA and decrease its affinity for the consensus DNA binding site. Structural characterization of this interaction revealed that one of the ring-fused 2-pyridones, compound 1, binds within a hydrophobic pocket, located between the C- and N-terminal domains of PrfA, and interacts with residues important for PrfA activation. This indicates that these inhibitors maintain the DNA-binding helix-turn-helix motif of PrfA in a disordered state, thereby preventing a PrfA:DNA interaction. Ring-fused 2-pyridones represent a new class of chemical probes for studying virulence in L. monocytogenes.

National Category
Biochemistry and Molecular Biology
Research subject
Molecular Biology
Identifiers
URN: urn:nbn:se:umu:diva-114083OAI: oai:DiVA.org:umu-114083DiVA: diva2:893601
Available from: 2016-01-12 Created: 2016-01-12 Last updated: 2016-02-29Bibliographically approved
In thesis
1. Regulatory pathways and virulence inhibition in Listeria monocytogenes
Open this publication in new window or tab >>Regulatory pathways and virulence inhibition in Listeria monocytogenes
2016 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Listeria monocytogenes is a rod-shaped Gram positive bacterium. It generally exist ubiquitously in nature, where it lives as a saprophyte. Occasionally it however enters the food chain, from where it can be ingested by humans and cause gastro-intestinal distress. In immunocompetent individuals L. monocytogenes is generally cleared within a couple of weeks, but in immunocompromised patients it can progress to listeriosis, a potentially life-threatening infection in the central nervous system. If the infected individual is pregnant, the bacteria can cross the placental barrier and infect the fetus, possibly leading to spontaneous abortion.

The infectivity of L. monocytogenes requires a certain set of genes, and the majority of them is dependent on the transcriptional regulator PrfA. The expression and activity of PrfA is controlled at several levels, and has traditionally been viewed to be active at 37 °C (virulence conditions) where it bind as a homodimer to a “PrfA-box” and induces the expression of the downstream gene.

One of these genes is ActA, which enables intracellular movement by recruiting an actin polymerizing protein complex. When studying the effects of a blue light receptor we surprisingly found an effect of ActA at non-virulent conditions, where it is required for the bacteria to properly react to light exposure.

To further study the PrfA regulon we tested deletion mutants of several PrfA-regulated virulence genes in chicken embryo infection studies. Based on these studies we could conclude that the chicken embryo model is a viable complement to traditional murine models, especially when investigating non-traditional internalin pathogenicity pathways. We have also studied the effects of small molecule virulence inhibitors that, by acting on PrfA, can inhibit L. monocytogenes infectivity in cell cultures with concentrations in the low micro-molar range.

Place, publisher, year, edition, pages
Umeå: Umeå Universitet, 2016. 37 p.
Series
Umeå University medical dissertations, ISSN 0346-6612 ; 1772
Keyword
Listeria monocytogenes, PrfA, ActA, infection
National Category
Cell and Molecular Biology
Research subject
Molecular Biology
Identifiers
urn:nbn:se:umu:diva-114085 (URN)978-91-7601-397-7 (ISBN)
Public defence
2016-02-04, KB3B1, KBC-huset, Umeå, 09:00 (English)
Opponent
Supervisors
Available from: 2016-01-14 Created: 2016-01-12 Last updated: 2016-01-26Bibliographically approved

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Good, James A. D.Andersson, ChristopherHansen, SabineWall, JessicaKrishnan, SyamGrundström, ChristinNiemiec, Moritz SebastianVaitkevicius, KarolisChorell, ErikSauer, Uwe H.Wittung-Stafshede, PernillaSauer–Eriksson, A. ElisabethAlmqvist, FredrikJohansson, Jörgen
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Department of ChemistryUmeå Centre for Microbial Research (UCMR)Department of Molecular Biology (Faculty of Medicine)Molecular Infection Medicine Sweden (MIMS)
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