An Important Step in<i>Listeria</i>Lipoprotein Research

Portillo, Francisco García‐del; Cossart, Pascale

doi:10.1128/jb.01577-06

Cited by 3 publications

(1 citation statement)

References 25 publications

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“…The LP2387 ::Tn mutant has a mutation mapped to LMOF2365_2387, which encodes a putative lipoprotein. Lipoproteins are a major category of bacterial surface proteins that have diverse functions and often have important effects on pathogen/host interactions ( García-del Portillo and Cossart, 2007 ; Machata et al, 2008 ). Up to 68 putative lipoproteins have been predicted in the genome of L. monocytogenes include ABC transporter lipoproteins for acquisition of micronutrients ( Baumgärtner et al, 2007 ).…”

Section: Discussionmentioning

confidence: 99%

Identification of genetic elements required for Listeria monocytogenes growth under limited nutrient conditions and virulence by a screening of transposon insertion library

et al. 2022

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Listeria monocytogenes, the causative agent of listeriosis, displays a lifestyle ranging from saprophytes in the soil to pathogenic as a facultative intracellular parasite in host cells. In the current study, a random transposon (Tn) insertion library was constructed in L. monocytogenes strain F2365 and screened to identify genes and pathways affecting in vitro growth and fitness in minimal medium (MM) containing different single carbohydrate as the sole carbon source. About 2,000 Tn-mutants were screened for impaired growth in MM with one of the following carbon sources: glucose, fructose, mannose, mannitol, sucrose, glycerol, and glucose 6-phosphate (G6P). Impaired or abolished growth of L. monocytogenes was observed for twenty-one Tn-mutants with disruptions in genes encoding purine biosynthesis enzymes (purL, purC, purA, and purM), pyrimidine biosynthesis proteins (pyrE and pyrC), ATP synthase (atpI and atpD2), branched-chain fatty acids (BCFA) synthesis enzyme (bkdA1), a putative lipoprotein (LMOF2365_2387 described as LP2387), dUTPase family protein (dUTPase), and two hypothetical proteins. All Tn-mutants, except the atpD2 mutant, grew as efficiently as wild-type strain in a nutrient rich media. The virulence of twenty-one Tn-mutants was assessed in mice at 72 h following intravenous (IV) infection. The most attenuated mutants had Tn insertions in purA, hypothetical protein (LMOf2365_0064 described as HP64), bkdA1, dUTPase, LP2387, and atpD2, confirming the important role of these genes in pathogenesis. Six Tn-mutants were then tested for ability to replicate intracellularly in murine macrophage J774.1 cells. Significant intracellular growth defects were observed in two Tn-mutants with insertions in purA and HP64 genes, suggesting that an intact purine biosynthesis pathway is important for intracellular growth of L. monocytogens. These findings may not be fully generalized to all of L. monocytogenes strains due to their genetic diversity. In conclusion, Tn-mutagenesis identified that biosynthesis of purines, pyrimidines, ATP, and BCFA are important for L. monocytogens pathogenesis. Purine and pyrimidine auxotrophs play an important role in the pathogenicity in other bacterial pathogens, but our study also revealed new proteins essential for both growth in MM and L. monocytogenes strain F2365 virulence.

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Section: Discussionmentioning

confidence: 99%

Identification of genetic elements required for Listeria monocytogenes growth under limited nutrient conditions and virulence by a screening of transposon insertion library

et al. 2022

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Analysis of Cell Envelope Proteins

Desvaux¹,

H√©braud²

2008

Handbook of Listeria Monocytogenes

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Lipoproteins of Listeria monocytogenes Are Critical for Virulence and TLR2-Mediated Immune Activation

Machata

Tchatalbachev

Mohamed

et al. 2008

The Journal of Immunology

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Numerous cell surface components of Listeria influence and regulate innate immune recognition and virulence. Here, we demonstrate that lipidation of prelipoproteins in Listeria monocytogenes is required to promote NF-κB activation via TLR2. In HeLa cells transiently expressing TLR2, L. monocytogenes and Listeria innocua mutants lacking the prolipoprotein diacylglyceryl transferase (lgt) gene are unable to induce TLR2-dependent activation of NF-κB, a property intrinsic to their isogenic parental strains. TLR2-dependent immune recognition is directed to secreted, soluble lipoproteins as evidenced by the sensitivity of the response to lipoprotein lipase. Studies of bone marrow-derived macrophages of C57BL/6 wild-type and TLR2-deficient mice infected with wild-type and lgt mutant strains indicate that the absence of host TLR2 receptor signaling has consequences similar to those of the absence of the bacterial TLR2 ligand, i.e., a delay in cellular immune responses directed toward the bacterium. Infection studies with the wild-type and TLR2−/− mice indicated attenuation of the lgt deletion mutant in both mouse strains, implying multiple roles of lipoproteins during infection. Further characterization of the Δlgt mutant indicated that it is impaired for both invasion and intracellular survival and exhibits increased susceptibility to cationic peptides. Our studies identify lipoproteins as the immunologically active ligand of TLR2 and assign a critical role for this receptor in the recognition of these bacteria during infection, but they also reveal the overall importance of the lipoproteins for the pathogenicity of Listeria.

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An Important Step inListeriaLipoprotein Research

Cited by 3 publications

References 25 publications

Identification of genetic elements required for Listeria monocytogenes growth under limited nutrient conditions and virulence by a screening of transposon insertion library

Identification of genetic elements required for Listeria monocytogenes growth under limited nutrient conditions and virulence by a screening of transposon insertion library

Analysis of Cell Envelope Proteins

Lipoproteins of Listeria monocytogenes Are Critical for Virulence and TLR2-Mediated Immune Activation

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